Don’t think I have the courage to potentially brick it yet by writing anything to the flash chip. When I get my Z620 I’ll see if I can get as far as dumping the bios. Not sure what happens if a checksum fails, perhaps no boot at all. I don’t think it’s impossible but HP seems to have started using checksumming of sections of the BIOS by the time these workstations came out. Somewhat related is modding of the BIOS, for example to add M2 NVMe boot support. For guaranteed success of powering the flash chip it probably takes either a good 3.3v external supply, desoldering the 3.3v pin, or desoldering the whole chip.
So there probably isn’t a way to get the motherboard to power the SPI chip without booting up. For desktops it appears the only power supplied with the PSU off would be 5v standby (per ATX standard which HP/Dell often ignore). Regarding the 3.3v drain of the motherboard, on ThinkPads it appears this can be avoided by disconnecting the 3.3v from the Pi (don’t want competing 3.3v!) and plugging the AC power adapter in. If flashing the entire BIOS file, one would need to hex-edit the MAC addresses and whatever else back in. Possibly even the CMOS battery too, just to be cautious.įlashing just the boot block is imporant because it seems there may be system-specific information stored on the BIOS flash like MAC addresses.
The specific SPI flash chip you have matters and its worth looking at the datasheet of the chip and how SPI wiring works.ĭisconnect everything from the motherboard before doing option 2) or 3). Allows one to avoid the flashing stage and might be easier for the more hardware inclined.īefore doing any of these, read up on how flashing BIOS chips works in general.