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Multiboot USB: Chromium OS with Grub2 and Grub4Dos


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#1 George.Harmony

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Posted 08 August 2011 - 05:01 AM

This how-to will show you how to install Chromium OS to a usb thumbdrive, then change the boot loader to Grub2 and finally create a hybrid MBR so we can load grub4dos from grub2.

This allows us to load almost anything we want. For me it is mainly Live CDs. See my menus in the appendix at the end. All items list boot and are usable.

Hopefully you find this useful. It is not pretty and there may be easier ways to do it but this method has worked for me on 2 separate thumbdrives and an sd card.

How-To:

This how-to will install ChromiumOS to a thumbdrive, replace the bootloader with Grub2 (to boot Linux ISOs) and then install Grub4Dos to a separate partition (to boot DOS/Windows based ISOs).

I used Arch Linux to create this tutorial but original research and first thumbdrive was created on PMagic 6.4 Live cd. Your mileage may vary if attempted on a different Linux OS.

1. Warnings and notes.

Always be sure which /dev/sdx refers to your thumbdrive. DD and installing grub2 to the wrong drive can destroy your data and leave your system unbootable. You have been warned!

Once you install ChromiumOS do not open the thumbdrive with any other partition editor but gdisk. Parted and gparted would ruin the file structure on me if i made any changes with them. Again YMMV.

In gdisk if you don't see a value beside the prompt in the codes below it means the default was accepted.

2. Tool required:

1 USB Thumbdrive of at least 4GB

Chromium OS Vanilla by Hexxeh release 0.14.805.2011_07_31_1705-r54807a91

DD <standard in most distros>

gdisk <installed with the gptfdisk package>

mkfs.vfat <installed with the dosfstools package>

grub2-bios 1:1.99-3 <this is the Arch Linux Package the one in Pmagic also worked with the commands below>

grub4dos 0.4.4 <download the files from sourceforge and extract the files to a directory>

3. Erase disk

dd if=/dev/zero of=/dev/sdb

replace sdb with the value for your thumbdrive.

4. Write image to disk

dd if=ChromeOS-Vanilla-0.14.805.2011_07_31_1705-r54807a91.img of=/dev/sdb bs=4096

5. Using gdisk

gdisk /dev/sdb

Extend disk to take utilize full disk.

go to extra functionality (experts only)

Command (? for help): x

relocate backup data structures to the end of the disk

Expert command (? for help): e

Relocating backup data structures to the end of the disk

create new partition in remaining space

Expert command (? for help): m



Command (? for help): n



Partition number (13-128, default 13): 



First sector (34-4005889, default = 16452) or {+-}size{KMGTP}: 



Last sector (16452-20479, default = 20479) or {+-}size{KMGTP}: 



Current type is &#39;Linux filesystem&#39;



Hex code or GUID (L to show codes, Enter = 8300): 0700



Changed type of partition to &#39;Microsoft basic data&#39;


Write the change to disk.

Command (? for help): w



Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING

PARTITIONS!!



Do you want to proceed? (Y/N): Y

OK; writing new GUID partition table (GPT).

The operation has completed successfully

6. Make vfat file system in new partition

mkfs.vfat /dev/sdb13

mkfs.vfat 3.0.11 (24 Dec 2010)

7. Install grub2

Grub2 does not like installing without a bios_grub flag on a partition but in trial anytime I set the flag nothing would boot so we will force the installation and let grub2 complain.

Mount root directory we want to use for grub2.

I use the boot directory that was created by Chromium on my thumbdrive

On my installation it is sdb12

To find out if yours is the same run

gdisk -l /dev/sdb

Password: 

GPT fdisk (gdisk) version 0.7.2



Partition table scan:

  MBR: protective

  BSD: not present

  APM: not present

  GPT: present



Found valid GPT with protective MBR; using GPT.

Disk /dev/sdb: 15644672 sectors, 7.5 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): F07CBA0D-1738-3C42-9B1B-92D7A2E76277

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 15644638

Partitions will be aligned on 1-sector boundaries

Total free space is 4058 sectors (2.0 MiB)



Number  Start (sector)    End (sector)  Size       Code  Name

   1         1810432         3907583   1024.0 MiB  0700  STATE

   2           20480           53247   16.0 MiB    7F00  KERN-A

   3           53248         1810431   858.0 MiB   7F01  ROOT-A

   4         3973120         4005887   16.0 MiB    7F00  KERN-B

   5         4005888         4005888   512 bytes   7F01  ROOT-B

   6           16448           16448   512 bytes   7F00  KERN-C

   7           16449           16449   512 bytes   7F01  ROOT-C

   8         3907584         3940351   16.0 MiB    0700  OEM

   9           16450           16450   512 bytes   7F02  reserved

  10           16451           16451   512 bytes   7F02  reserved

  11              64           16447   8.0 MiB     FFFF  RWFW

  12         3940352         3973119   16.0 MiB    EF00  EFI-SYSTEM

  13         4005889        15644638   5.5 GiB     0700  Microsoft basic data


and look for the EFI-SYSTEM name.

12         3940352         3973119   16.0 MiB    EF00  EFI-SYSTEM

mount /dev/sdb12 /mnt/cards/


Install grub2

grub-install --no-floppy --root-directory=/mnt/cards/ --force /dev/sdb12



/sbin/grub-setup: warn: Attempting to install GRUB to a partitionless disk or to a partition.  This is a BAD idea..

/sbin/grub-setup: warn: Embedding is not possible.  GRUB can only be installed in this setup by using blocklists.  However, blocklists are UNRELIABLE and their use is discouraged..

Installation finished. No error reported.

Create a grub.cfg

I am going to assume you have a working grub.cfg somewhere so feel free to reuse it. If you don't my full one is below. I have a lot of crap in my mine so unfortuantly i'm not a 100% sure what is required and what is not but here is the important entry to boot Chromium


menuentry "Chromium OS" {

	linux (hd0,3)/boot/vmlinuz quiet console=tty2 init=/sbin/init boot=local rootwait ro noresume noswap loglevel=1 noinitrd root=/dev/sdb3 i915.modeset=1 cros_efi

}


be sure to save the grub.cfg to the boot/grub/ directory on your thumbdrive. The directory will be in your file tree where you mounted your thumbdrive above.

Unmount the boot directory

umount /mnt/cards/

8. Create a hybrid MBR so we can load grub4dos

gdisk /dev/sdb

go to recovery and transformation options (experts only)

Command (? for help): r

choose make hybrid MBR

Recovery/transformation command (? for help): h



WARNING! Hybrid MBRs are flaky and dangerous! If you decide not to use one,

just hit the Enter key at the below prompt and your MBR partition table will

be untouched.



Type from one to three GPT partition numbers, separated by spaces, to be

added to the hybrid MBR, in sequence:13



Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): y



Creating entry for GPT partition #13 (MBR partition #2)

Enter an MBR hex code (default 07): 0c

Set the bootable flag? (Y/N): n



Unused partition space(s) found. Use one to protect more partitions? (Y/N): y

Note: Default is 0xEE, but this may confuse Mac OS X.

Enter an MBR hex code (default EE): 0a



Recovery/transformation command (? for help): w



Warning! Mismatched GPT and MBR partition! MBR partition 4, of type 0x0A,

has no corresponding GPT partition! You may continue, but this condition

might cause data loss in the future!



Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING

PARTITIONS!!



Do you want to proceed? (Y/N): y

OK; writing new GUID partition table (GPT).

The operation has completed successfully

9. Install grub4dos

Mount the partition you created with gdisk the first time around

mount /dev/sdb13 /mnt/cards/[code]



make a boot/grub directory



[code]mkdir -p /mnt/cards/boot/grub[/code]



copy files from your grub4dos that you downloaded and extracted earlier



[code]cp grub.exe grldr /mnt/cards/boot/grub/[/code]



create a menu.lst and place it in with the grub.exe and grldr files on your thumbdrive



again mine is listed below.



and finally add the entry for grub4dos to your grub.cfg



[code]umount /mnt/cards/

mount /dev/sdb12 /mnt/cards/

add this entry to your grub.cfg

menuentry &#39;Other Live CDs&#39;{

	set root=&#39;(hd0,1)&#39;

	linux (hd0,gpt13)/boot/grub/grub.exe 

}

umount /mnt/cards/

and finally reboot to your new thumbdrive.

10.Appendix

grub.cfg


### BEGIN /etc/grub.d/00_header ###

insmod part_gpt

insmod part_msdos

insmod fat

if [ -s $prefix/grubenv ]; then

  load_env

fi

set default="0"

if [ "${prev_saved_entry}" ]; then

  set saved_entry="${prev_saved_entry}"

  save_env saved_entry

  set prev_saved_entry=

  save_env prev_saved_entry

  set boot_once=true

fi



function savedefault {

  if [ -z "${boot_once}" ]; then

    saved_entry="${chosen}"

    save_env saved_entry

  fi

}



function load_video {

  insmod vbe

  insmod vga

  insmod video_bochs

  insmod video_cirrus

}



set menu_color_normal=green/black

set menu_color_highlight=black/green



insmod part_msdos

insmod ext2

set root=&#39;(hd0,msdos1)&#39;

search --no-floppy --fs-uuid --set=root 908d3c4a-4884-44b1-b153-96a10dbfb2b2

if loadfont /grub/unicode.pf2 ; then

  set gfxmode=1024x600x32

  load_video

  insmod gfxterm

  insmod part_msdos

  insmod ext2

  set root=&#39;(hd1,msdos1)&#39;

  search --no-floppy --fs-uuid --set=root 908d3c4a-4884-44b1-b153-96a10dbfb2b2

  set locale_dir=($root)/grub/locale

  set lang=en_US

  insmod gettext

fi

terminal_input console

terminal_output gfxterm

set timeout=5

### END /etc/grub.d/00_header ###



### BEGIN /etc/grub.d/20_linux_xen ###

### END /etc/grub.d/20_linux_xen ###



### BEGIN /etc/grub.d/20_memtest86+ ###

### END /etc/grub.d/20_memtest86+ ###



### BEGIN /etc/grub.d/30_os-prober ###

### END /etc/grub.d/30_os-prober ###



### BEGIN /etc/grub.d/40_custom ###

# This file provides an easy way to add custom menu entries.  Simply type the

# menu entries you want to add after this comment.  Be careful not to change

# the &#39;exec tail&#39; line above.

menuentry &#39;Arch Linux, BFS Kernel&#39; --class archlinux --class gnu-linux --class gnu --class os {

	load_video

	set gfxpayload=keep

	insmod gzio

	insmod part_msdos

	insmod ext2

	set root=&#39;(hd1,msdos1)&#39;

	search --no-floppy --fs-uuid --set=root 908d3c4a-4884-44b1-b153-96a10dbfb2b2

	echo	&#39;Loading Linux vmlinuz26-bfs ...&#39;

	linux	/vmlinuz26-bfs root=/dev/mapper/vgroup-root cryptdevice=/dev/sda2:vgroup ro  quiet

	echo	&#39;Loading initial ramdisk ...&#39;

	initrd	/kernel26-bfs.img

}



menuentry &#39;Arch Linux, Stock Kernel&#39; --class archlinux --class gnu-linux --class gnu --class os {

	load_video

	set gfxpayload=keep

	insmod gzio

	insmod part_msdos

	insmod ext2

	set root=&#39;(hd1,msdos1)&#39;

	search --no-floppy --fs-uuid --set=root 908d3c4a-4884-44b1-b153-96a10dbfb2b2

	echo	&#39;Loading Linux vmlinuz26 ...&#39;

	linux	/vmlinuz26 root=/dev/mapper/vgroup-root cryptdevice=/dev/sda2:vgroup ro  quiet

	echo	&#39;Loading initial ramdisk ...&#39;

	initrd	/kernel26-fallback.img

}



menuentry "Chromium OS" {

	linux (hd0,3)/boot/vmlinuz quiet console=tty2 init=/sbin/init boot=local rootwait ro noresume noswap loglevel=1 noinitrd root=/dev/sdb3 i915.modeset=1 cros_efi

}



menuentry &#39;Parted Magic 6.4&#39;{

	set root=&#39;(hd0,gpt13)&#39;

	loopback loop (hd0,gpt13)/pmagic-6.4.iso

	linux (loop)/pmagic/bzImage edd=off load_ramdisk=1 prompt_ramdisk=0 rw loglevel=9 vga=normal livemedia noeject max_loop=256 vmalloc=256MiB

	initrd (loop)/pmagic/initramfs

}



menuentry &#39;Backtrack 5&#39;{

	set root=&#39;(hd0,gpt13)&#39;

	loopback loop (hd0,gpt13)/BT5-GNOME-32.iso

	linux (loop)/casper/vmlinuz file=/cdrom/preseed/custom.seed boot=casper initrd=(hd0,gpt13)/boot/initrdBT.gz iso-scan/filename=/BT5-GNOME-32.iso noeject noprompt splash --

	initrd (hd0,gpt13)/boot/initrdBT.gz

}



menuentry &#39;Other Live CDs&#39;{

	set root=&#39;(hd0,1)&#39;

	linux (hd0,gpt13)/boot/grub/grub.exe --config-file=/boot/grub/menu.lst

}



### END /etc/grub.d/40_custom ###



### BEGIN /etc/grub.d/41_custom ###

if [ -f  $prefix/custom.cfg ]; then

  source $prefix/custom.cfg;

fi

### END /etc/grub.d/41_custom ###


my Backtrack has a respun initrd. If you'd like the script to rework yours just ask.

menu.lst


color green/black black/green green/black green/black

timeout 30

default /default



title Ultimate Boot CD 5.03

 find --set-root /ubcd503.iso

 map (hd0,1)/ubcd503.iso (hd32)

 map --hook

 chainloader (hd32)



title Kolibrios

 find --set-root /kolibri.iso

 map (hd0,1)/kolibri.iso (0xff) || map --mem (hd0,0)/kolibri.iso

 map --hook

 chainloader (0xff)



title OphCrack XP 2.3.1 (XP Password Cracker)

 find --set-root /ophcrack-xp-livecd-2.3.1.iso

 map /ophcrack-xp-livecd-2.3.1.iso (0xff)

 map --hook

 root (0xff)

 kernel /boot/bzImage rw root=/dev/null vga=normal lang=C kmap=uk screen=1024x768x16 autologin

 initrd /boot/rootfs.gz 



title OphCrack Vista 2.3.1 (Vista Password Cracker)

 find --set-root /ophcrack-vista-livecd-2.3.1.iso

 map /ophcrack-vista-livecd-2.3.1.iso (0xff)

 map --hook

 root (0xff)

 kernel /boot/bzImage rw root=/dev/null vga=normal lang=C kmap=uk screen=1024x768x16 autologin

 initrd /boot/rootfs.gz 



title Win7PE Plain

 map (hd0,1)/win7PE_SEV4Disk1.ISO (hd32)

 chainloader (hd0,1)+1

 map --hook

 chainloader (hd32)

 boot



title Win7PE Tools

 map (hd0,1)/win7PE_SEV4Disk2.ISO (hd32)

 chainloader (hd0,1)+1

 map --hook

 chainloader (hd32)

 boot



title Kon-Boot v1.1

 map --mem (hd0,1)/konFloppy.img (fd0)

 map --hook

 chainloader (fd0)+1

 map (hd1) (hd0)

 map --hook

 rootnoverify (fd0)



title Reboot

 reboot



title Halt

 halt



title Command-line

 commandline


11.Reference

This site and the ones list below were invaluable in figuring this out

http://www.rodsbooks...isk/hybrid.html

http://www.win.tue.n...on_types-1.html

#2 Wonko the Sane

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Posted 08 August 2011 - 11:16 AM

Nice work! :thumbup: :confused1:

Is it correct (assumed by the "overall plot" of your niice post) that Chromium OS only works/installs on GPT disks? ;) :cheers:

:cheers:
Wonko

#3 George.Harmony

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Posted 08 August 2011 - 01:04 PM

Nice work! :thumbup: :confused1:

Is it correct (assumed by the "overall plot" of your niice post) that Chromium OS only works/installs on GPT disks? ;) :cheers:

:cheers:
Wonko


You are correct. Also if you try to make any changes to the Chromium files or file system (except for creating the hybrid MBR) Chromium will rebuild itself and destroy them.

Can anyone verify that the above worked for them?

#4 Wonko the Sane

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Posted 08 August 2011 - 01:41 PM

You are correct. Also if you try to make any changes to the Chromium files or file system (except for creating the hybrid MBR) Chromium will rebuild itself and destroy them.


I find it difficult to believe it nonetheless.:cheers:

Maybe it is a (mind-boggling foolish :cheers:, IMNSHO) "feature" of the specific "Hexxeh" build. :confused1:

Most probably converting to "plain" the VMware thingy will make a "MBR compatible" Chromium "Vanilla". :thumbup:

It seems like there is also "flow":
http://chromeos.hexxeh.net/index.php
(though I have no idea if it uses the same GPT partitioning)

Thank you very much for your nice info and tutorial! ;)

:(
Wonko

#5 steve6375

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Posted 08 August 2011 - 01:51 PM

For Info

if you just use the Chrome Image file (Flow) to 'dd' it onto a USB stick, these are the first sectors
Spoiler


#6 George.Harmony

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Posted 08 August 2011 - 02:43 PM

I find it difficult to believe it nonetheless.:w00t:

Maybe it is a (mind-boggling foolish :), IMNSHO) "feature" of the specific "Hexxeh" build. ;)

Most probably converting to "plain" the VMware thingy will make a "MBR compatible" Chromium "Vanilla". :cheers:

It seems like there is also "flow":
http://chromeos.hexxeh.net/index.php
(though I have no idea if it uses the same GPT partitioning)

Thank you very much for your nice info and tutorial! :unsure:

:cheers:
Wonko


I never did look at the VHD images so I'm not sure if the file system on them is the same. I did download a couple of live Chromium images and they all did have the same file system inside.

I am using the hexxeh nightly builds for this tutorial from here. Are they much different form his regular release? I just followed his instructions on his main page "(bleeding edge, try this first!)"


There is also a tutorial on making ubuntu and chromium work together. I tried to modify for my purposes but could not get it to work and it seemed old. If someone wants to try that, here it is. I'd be interested to know if it was just me or if things have changed enough that it is no longer relevant.

@ steve6375

I noticed that when I was working away but didn't know how to use it to advantage. Any ideas? From what I understand I think it is just part of the OS's protective MBR which cannot be used like a hybrid MBR, afaik. From what I understand it is there to protect the gpt table from being overwritten by fdisk like utilities in error that are GPT unaware.

I would like to point out that this was all figured out by trial and error and a lot of this is completely new to me so what may be obvious to others I may miss and might ask lots of questions on information provided. Thanks in advance.

#7 steve6375

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Posted 08 August 2011 - 02:51 PM

It is all new to me too! I think EFI BIOSes will recognise the partition type and use EFI booting. If you try to run the USB stick from Oracle VM or QEMU it just continuously reboots!
So I think systems are using the EFI BIOS to boot this image (but I well may be wrong!).
Partition type EE is an MBR partition type which indicates an EFI partition header follows it. I guess the BIOS will start to do a normal MBR boot, see a type EE active partition and then use EFI to boot the EFI header which follows the MBR sector???Posted Image So unless grub4dos (or some other bootloader) supports EFI booting, it sounds difficult to do with a normal MBR bootloader...

#8 George.Harmony

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Posted 08 August 2011 - 03:03 PM

It is all new to me too! I think EFI BIOSes will recognise the partition type and use EFI booting. If you try to run the USB stick from Oracle VM or QEMU it just continuously reboots!
So I think systems are using the EFI BIOS to boot this image (but I well may be wrong!).
Partition type EE is an MBR partition type which indicates an EFI partition header follows it. I guess the BIOS will start to do a normal MBR boot, see a type EE active partition and then use EFI to boot the EFI header which follows the MBR sector???Posted Image So unless grub4dos (or some other bootloader) supports EFI booting, it sounds difficult to do with a normal MBR bootloader...


You are on the right track. If the system didn't support a GPT Boot it would got to partition 12 and boot from there as far as I could tell. Once the Syslinux bootloader started it would start a regular EFI boot. I tried changing the syslinux config files on partition 12 after installing an booting grub2 but I ran into a bunch of issues with that and ultimately I really wanted grub4dos on the disk too for loading dos based ISO's like UBCD and winpe7_se. So without the hydrid MBR and with G4D being gpt unaware I wouldn't have accomplished what I wanted.

Also as stated above I really believe those entries you pointed out are only for protecting the gpt from utilities that are gpt unaware.

#9 steve6375

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Posted 08 August 2011 - 03:09 PM

The MBR code looks like it is looking for a GPT partition as it has 'GPT' in it. I would be interested to see a disassembly of this code - my guess is that it makes some sort of BIOS call to an EFI BIOS boot routine. Maybe I will have to disassemble it myself to see what it does...

http://en.wikipedia....Partition_Table

#10 Wonko the Sane

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Posted 08 August 2011 - 03:20 PM

@steve6375
EFI and GPT not necessarily go together.
The "MBR" (which is not actually a "MBR" is the so called "protective MBR").
The WHOLE (or at least most) of the story is on the already referenced pages of gdisk:
http://www.rodsbooks.com/gdisk/

See also this seemingly unrelated thread:
http://reboot.pro/11600/

The real issue as I see it is not really grub4dos (I guess one can start a grub.exe and give to it some "map" commands), but rather the actual OS you want to run:
http://reboot.pro/11600/page__st__32
that may or may not support the GPT partitioned disk.

See this also:
http://reboot.pro/15117/

;)
Wonko

#11 George.Harmony

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Posted 08 August 2011 - 03:20 PM

The MBR code looks like it is looking for a GPT partition as it has 'GPT' in it. I would be interested to see a disassembly of this code - my guess is that it makes some sort of BIOS call to an EFI BIOS boot routine. Maybe I will have to disassemble it myself to see what it does...

http://en.wikipedia....Partition_Table


That would make sense since the OS is meant to boot on their own netbooks and they probably embed some of the data right to their bios. If that is what you are getting at.

#12 George.Harmony

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Posted 22 August 2011 - 03:24 PM

So after some more playing with this I have figured out how to do it on mbr partitioning scheme. Basically I used dd to grab the partitions out of the image. Created my mbr with fdisk so partition 1 and 3 were the same size as partitions 1 and 3 of the Chrome image. Then I used dd to write the extracted partitions to the drive. After that I simply installed Grub2 and grub4dos as per usual.

A couple of things I noticed.

1. The partitions for ChromeOS to work must be 1 and 3. If anyone can figure out how to get around this i would be most appreciative since ChromeOS on partition 1 leads me to my next point.

2. Windows cannot read partitions that come after partitions it does not understand. So a device used for chrome os means the disk cannot be accessed from within a windows environment since Windows does not understand the chromeOS file system. Win Live Cds will work but cannot access the thumbdrive so no storage for portable apps or documents unless you have another thumbdrive available.

If anyone would like the tutorial for MBR ChromeOS just ask and I will post one. I kept notes and could probably throw together a post on it.

#13 Wonko the Sane

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Posted 22 August 2011 - 03:47 PM

2. Windows cannot read partitions that come after partitions it does not understand. So a device used for chrome os means the disk cannot be accessed from within a windows environment since Windows does not understand the chromeOS file system. Win Live Cds will work but cannot access the thumbdrive so no storage for portable apps or documents unless you have another thumbdrive available.

There is something that doesn't "sound right" either in your description or in the way I understand it :ph34r:, you are not falling for the "no more than one partition on removable devices, aren't you? :unsure:
(flipped removable bit or cfadisk.sys or dummydisk.sys filter drivers)

Of course Windows, unless it has an apt filesystem driver is not able to access a filesystem it knows nothing about.

:cheers:
Wonko

#14 George.Harmony

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Posted 22 August 2011 - 04:32 PM

There is something that doesn't "sound right" either in your description or in the way I understand it :ph34r:, you are not falling for the "no more than one partition on removable devices, aren't you? :unsure:
(flipped removable bit or cfadisk.sys or dummydisk.sys filter drivers)

Of course Windows, unless it has an apt filesystem driver is not able to access a filesystem it knows nothing about.

:cheers:
Wonko


I could be missing something. I know you can get more partitions than 1 on a usb stick and windows will see them all.

I am using win7pe_se as my windows test machine since I am a linux guy and don't have an actual install of windows anywhere.

I did try a few ways. I tried to make the first hybrid partition in my tutorial above match the front of the drive.

I tried making the 2nd partition of the MBR only style disk be at the front of the drive.

I also put the chromeos partitions on 2 and 3 and when I did this win7pe_se would see the 1st partition and be able to use it but chromeOS seems hardwired to be on partition 1 and 3 and would not boot. I thought I saw a way around this while doing my research but could not find the thread again. Typical eh?

Just so we are clear any partition I created that was not for chrome were formated either with fat16 or fat32 depending on the size.

Of course I don't expect windows to access ext3 or ext2 I just want it to ignore them completely but when I load up disk management in windows it has given the 1st fat partition, (partition2, since 1 and 3 are occupied by ChromeOS) a drive letter and shows it as a raw partition. If I try to go into it it wants to format it. This happens whether I boot win7pe-se from the thumbdrive chromeos is installed on or if it is booted from a different drive.

Can you clarify what you mean about

(flipped removable bit or cfadisk.sys or dummydisk.sys filter drivers)

. I'm not sure what you mean.

BTW I'm not done with this yet. I have just taken a break. I have to build my own win7pe and insert qemu into it and an iso. I built a Microcore ISO that mounts all the drives attached to qemu machine and redirect port 445 from the host to the guest machine. Basically you can then access the gpt drive across ms shared folders. This gives me access to the files on the thumbdrive. Its a kludge but it works well enought for me if I can't get Windows to see the thumbdrive with ChromeOS on it.

It also has the added benefit that if you boot it directly on the machine it will mount every drive it finds and then share them on the network. To access you simple type in the ip address and the hard drive as such \\192.168.X.X\hda1. I can share it if anyone is interested.

#15 Wonko the Sane

Wonko the Sane

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Posted 22 August 2011 - 04:54 PM

Can you clarify what you mean about . I'm not sure what you mean.

See here:
http://www.msfn.org/...os/page__st__54

As I see it, a Windows NT if the Removable bit of the device (USB stick) is set, won't access anything but the First partiton.
You need to either flip the bit of the device (tricky and in some cases impossible) or use a filter driver.

Or there is something "wrong" in the FDISK thingy :dubbio:
Can you dd just the MBR of the stick, compress it into a .zip, upload it "somewhere" and post a link to it?

:cheers:
Wonko

#16 George.Harmony

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Posted 22 August 2011 - 05:57 PM

Might be a day or two but sure. Currently I am working on a multiboot 16 gig stick without ChromiumOS. I do need to rebuild my sd card for my laptop to the MBR only scenario since I definitely want ChromiumOS on that and am willing to give up windows access on the card since I usually have the key handy when I use it.




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