Is there a sure-fire way to reset any BIOS flash image to its default, out-of-the-box state with no special equipment?
Hi, I am seeking an answer to an apparently obscure question. If I install coreboot on my BIOS (UEFI motherboard) and the computer fails to boot, can I reset the BIOS flash to its default image? I've read about possibly changing jumper positions or removing the BIOS battery, but I can't seem to establish if these are sure-fire ways of restoring the original BIOS flash image. I'd like to attempt to install coreboot on a motherboard that doesn't appear to be coreboot-supported, but only if I know I can completely undo this. Is the default BIOS flash image preserved somewhere on a ROM chip or can it only be restored with special equipment? I definitely do not want to end up with an unusable machine. Thanks! Jim
On Fri, 21 Feb 2014 21:47:58 -0800 linx255@nym.hush.com wrote:
Hi, I am seeking an answer to an apparently obscure question. If I install coreboot on my BIOS (UEFI motherboard) and the computer fails to boot, can I reset the BIOS flash to its default image? I've read about possibly changing jumper positions or removing the BIOS battery, but I can't seem to establish if these are sure-fire ways of restoring the original BIOS flash image. I'd like to attempt to install coreboot on a motherboard that doesn't appear to be coreboot-supported, but only if I know I can completely undo this. Is the default BIOS flash image preserved somewhere on a ROM chip or can it only be restored with special equipment? I definitely do not want to end up with an unusable machine. Thanks!
Hi, simple answer: no. The code in the flash chip does initialize the most basic functions of a mainboard. Without it there is no way to recover. Also, coreboot needs to be ported to unsupported boards, it is not generic enough to just be written to any board and just work (this is actually not coreboot's fault, but is a consequence of the hardware design of x86 computers). If your flash chip is socketed, the easiest and cheapest way is to get a spare chip and to use hot-swapping... but usually getting an external programmer makes more sense. -- Kind regards/Mit freundlichen Grüßen, Stefan Tauner
Thanks for your helpful info! My motherboard has no removable chips. What kind of programming device would you recommend for a cutting edge Intel server board? It's one of those 4" x 4" boards with everything compacted into one giant iCore3 chip. I don't know that the BIOS/UEFI functionality is built into that or other non-removable ICs elsewhere on the board. And if I get an appropriate programming device can one easily / readily learn to use it to read and write code? I'm familiar with basic programming concepts, having worked with bash script, C, php, tcl, perl, html, et al. No knowledge of how to adapt generic coreboot BIOS code to a specific motherboard. Is it a matter of telling it what hardware to look for? I imagine there may be all kinds of board-specific devices and functions that only an Intel designer or engineer would know about. And even if I correctly port the code it seems I could still risk damaging the flash with a misstep of using the programmer—is that right? On February 22, 2014 at 5:31 AM, "Stefan Tauner" <stefan.tauner@student.tuwien.ac.at> wrote:
On Fri, 21 Feb 2014 21:47:58 -0800 linx255@nym.hush.com wrote:
Hi, I am seeking an answer to an apparently obscure question. If I install coreboot on my BIOS (UEFI motherboard) and the computer fails to boot, can I reset the BIOS flash to its default image? I've read about possibly changing jumper positions or removing the BIOS battery, but I can't seem to establish if these are sure-fire ways of restoring the original BIOS flash image. I'd like to attempt to install coreboot on a motherboard that doesn't appear to be coreboot-supported, but only if I know I can completely undo this. Is the default BIOS flash image preserved somewhere on a ROM chip or can it only be restored with special equipment? I definitely do not want to end up with an unusable machine. Thanks!
Hi,
simple answer: no. The code in the flash chip does initialize the most basic functions of a mainboard. Without it there is no way to recover. Also, coreboot needs to be ported to unsupported boards, it is not generic enough to just be written to any board and just work (this is actually not coreboot's fault, but is a consequence of the hardware design of x86 computers). If your flash chip is socketed, the easiest and cheapest way is to get a spare chip and to use hot-swapping... but usually getting an external programmer makes more sense.
-- Kind regards/Mit freundlichen Grüßen, Stefan Tauner
On Mon, 24 Feb 2014 23:54:40 -0800 linx255@nym.hush.com wrote:
Thanks for your helpful info!
My motherboard has no removable chips. What kind of programming device would you recommend for a cutting edge Intel server board? It's one of those 4" x 4" boards with everything compacted into one giant iCore3 chip. I don't know that the BIOS/UEFI functionality is built into that or other non-removable ICs elsewhere on the board. And if I get an appropriate programming device can one easily / readily learn to use it to read and write code? I'm familiar with basic programming concepts, having worked with bash script, C, php, tcl, perl, html, et al. No knowledge of how to adapt generic coreboot BIOS code to a specific motherboard. Is it a matter of telling it what hardware to look for? I imagine there may be all kinds of board-specific devices and functions that only an Intel designer or engineer would know about. And even if I correctly port the code it seems I could still risk damaging the flash with a misstep of using the programmer—is that right?
Physically damaging the chip or board is seldom an issue, but the other problems you mention are a major problem. Coreboot contains a lot of code for all kinds of devices and often it is only a matter of telling it which there are and how they are connected, but if you have to write support for new hardware from scratch, there is often no documentation at all for it... only good reverse engineers are then able to produce something workable. All of this is actually not really related to flashrom. Please refer to the coreboot mailing list and documentation if you still want to pursue this topic, thanks. -- Kind regards/Mit freundlichen Grüßen, Stefan Tauner
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Stefan Tauner