Greetings,
It IS possible to render a board unbootable with a bad flash, but there are a few protections in place.
The trickiest part is the initial loading where a fallback image is flashed into the top of the BIOS. The fallback block can (should) be set up as a completely independant boot image with a copy of Etherboot built in.
Most of the boards have a socketed flash so that the worst case scenerio for a mis-flashed fallback is that you'll have to boot from a spare chip, hot swap in the mis-flashed chip, and try again.
Unfortunatly, a few boards do have a soldered down flash. In those cases, the only way to recover is to de-solder the chip (which may not be worth the cost vs. a new board)
Once in place and functioning, the fallback should never be changed. Many mainboards (all of the i7501 based boards for example) have a jumper that can be set to prevent accidental flashing of the top block.
The rest of the flash contains the primary LinuxBIOS image and the preferred boot payload (often another copy of Etherboot), and can then be flashed at will. The worst case will be that you'll have to hit reset a few times to cause the fallback image to boot the system.
G'day, sjames
On Fri, 15 Aug 2003, Andrew Sterling Hanenkamp wrote:
According to the FAQ, it's possible to boot Linux using Etherboot with LinuxBIOS. This appears to be a pretty simple and straightforward process, but I was wandering if it were possible to render the system unbootable? That is, is it posible that overwriting the BIOS will cause boot to fail (because of misconfiguration, etc.)? If this happens, is there anyway to recover? What are the pitfalls and how can I avoid them?
The idea of overwriting the BIOS makes me a bit nervous, but the potential benefits of this boot-up process could save us quite a bit when it comes to configuring our clustered systems.
Thanks, Sterling