Lot of questions.
To follow the "they MUST have it tested approach", the 2K/XP MBR is the "most tested" one, but the Windows Vista /7 may have now a greater popularity.
I guess that it is a good idea to use the "new" one, but for a different reason, not because the BIOS programmers have necessarily tested it (at least they cannot have done it for anything manufactured before, say, 2006) but because the good MS guys (the good guys of "Embedded") have given to the other guys (of the "normal" MS OS's) some of their code, that has been designed to "better" boot from USB.
And came a lot of answers and information, I appreciate .
Seems that Steve also thought like you and added the "Win NT 6.x MBR" as the default "standard MBR" to his RmprepUsb. I supposed you would recommend 2K/XP MBR, since it might hopefully be tested with both old and new Mobos; now clear that i was wrong.
After seeing this and the links, i decided to quit seeking for an ultimate solution for the most bootable UFD.
BTW I lied , since a number of motherboards had issues with the actual 2K/XP (yes, it's OK to call it "Win NT 5.x MBR") the good guys from HP (another lie, they must have been the good guys from A-Data or M-Systems, cannot remember, but the so called "HP USB format tool" was NOT created originally by HP) still with a limited number of neurons, introduced a patch to it, see here:
that has often worked "better".
I think i understood the situation. Even if i install grldr.mbr and keep the "standard NT MBR" (and set a hot-key); i also have to keep the NT Boot record on the PBR. If i intend to install syslinux afterwards, keeping the "standard NT MBR" will be useless probably.
grub4dos grldr.mbr has been designed to store the "previous" MBR on second sector (in the sense that second sector is "empty" and ready to be filled with a MBR) , BUT, depending on the way it is installed it may be actually copied to it and/or prompt for a "hot-key" to boot it or not.
(if it is actually copied, but a hot-key for it is not set, then it is pretty much unuseful during booting)
Yes, exactly. But i already use the "simulated" CDROM device (Autorun Area) for WinXP.iso loading. There are also "Security Area" and another "Public Area" options but i never used these to date. And I'm not willing to, because i think so many different kind of partitions may affect the proper booting of the UFD or cause some other problems. Maybe some time later i can try but any probable solution will NOT be as efficient/handy as the hardware write-protect switch, unfortunately
About safety, instead of making the partition read only, you could use (not on all USB sticks, only on those that support it) the "simulated" CDROM device, but again there is no guarantee that it will be "universal".
After considering all the situations, i decided to keep my two UFDs as they are now. If one fails to boot properly on a specific machine, i will try the other. If it also fails, i will prepare again with the other options, MBR/PBR etc.
so many thanks to you, I really appreciate. Not because of the information and answers you provided here only, but also the other posts all over the forum. I read so many of yours on the other topics and learned a lot. Kudos
Edited by entorun, 02 October 2012 - 05:29 PM.