8 replies to this topic

[patrickdrd]

hello everyone,

 

I created a multi-boot usb (fat32 formatted) with winsetupfromusb on my uefi system (secure boot enabled) and,

while I get a menu showing me the two windows 10 & 8.1 entries I created,

I cannot see the initial menu or the options for the custom iso bootable images (grub4dos),

any ideas?

Edited by patrickdrd, 30 June 2017 - 06:13 AM.

[steve6375]

On a modern system which has a uefi bios you can boot in uefi mode or the old bios mode. Grub4dos can only boot in MBR mode so you will only see that menu with the non_uefi menu if you boot in MBR mode.
To boot in MBR mode change the bios setting to disable secure and fast boot and enable csm/legacy mode.
Then you should get two boot options for the usb drive.

[patrickdrd]

Well, ok but as far as I know booting in MBR/old bios doesn't have the same effects regarding the underlying system, right?

 

I mean, isn't it better to boot in uefi, when your system is uefi?

I had to open command prompt to type some bootrec commands a while ago and
I think I had to boot in uefi mode in order to view my disk and partition in the way uefi does.

 

Another example is, if you turn off uefi and secure boot, the underlying system refuses to boot (in windows).

 

In any case, you mean that it isn't possible to create a multi-boot usb with custom iso images entries and have it boot in uefi,

even if it's created in fat32?

 

I think the problem lies in the menu though, since I had an acronis bootable usb and I managed to boot in it,

but once again I wasn't able to view the options offered by it (i.e. "press 1 for true image and 2 for report)

Edited by patrickdrd, 30 June 2017 - 09:59 AM.

[steve6375]

Many ISOs and other bootable payloads do not support UEFI-booting.

e.g. you cannot boot to DOS or XP using UEFI because they need the old MBR\Legacy BIOS and cannot be run from a UEFI BIOS.

Many other ISOs (linux and WinPE) do not have the required UEFI boot files and\or do not support UEFI booting.

 

re. booting to Windows, I did not say you should disable UEFI in the BIOS settings, I said to enable MBR\Legacy booting so that you can boot via UEFI or MBR.

[patrickdrd]

re. booting to Windows, I did not say you should disable UEFI in the BIOS settings, I said to enable MBR\Legacy booting so that you can boot via UEFI or MBR.

Isn't there a contradiction in that? If I enable mbr/legacy, uefi has to be disabled,

I don't think my motherboard supports both at the same time (toshiba satellite laptop)

[steve6375]

Most BIOSes have an option to enable CSM mode without disabling UEFI.

If yours doesn't, then you will have to switch between CSM and UEFI depending on what you want to boot to.

[patrickdrd]

exactly! mine doesn't, uefi has to be enabled or disabled only,

anyway, thanks

[naruto1979]

I think the problem is the bootloader...

[patrickdrd]

yeah, could be, any suggestions on how to identify it and fix it?