[Syonyk]

Yes, in some cases. The common case for this would be writing the flash chip ("Updating the BIOS"). Some boards are more cautious about this than others, and a lot of "enthusiast" (overclocker) boards have dual BIOS chips, so you can always swap to a working one and then reflash the corrupted one. But very few modern systems will tolerate a power cut in the middle of a firmware update very well, and even if it does, it's often in a "Well, now, create this particular USB stick with exactly this filename on a FAT16 partition, boot it with it plugged into this particular USB port, and it might recover things" sort of method.

You'll notice most laptops refuse to update their firmware without the battery reasonably fully charged, and the power adapter plugged in. This is why.

And then we get into the definition of "irreversible." Yes, you can recover from this with an external SPI flasher, if you can get the firmware image into the proper state for the SPI flash, or have an image from before. But most people don't have this option.

As for hard drives, I'm of the impression that most newer drives will handle a power cut by using the inertia left in the platters and the motor-as-generator long enough to drive the heads back to a safe position, but I've not done any sort of in depth experimentation on it. A drive with a parking ramp for the heads (or a parking track) has those things for a reason, and "scraping the coating as the drive spins up somewhere in the data section" isn't good for drive longevity.

[jmholla]

> But very few modern systems will tolerate a power cut in the middle of a firmware update very well, and even if it does, it's often in a "Well, now, create this particular USB stick with exactly this filename on a FAT16 partition, boot it with it plugged into this particular USB port, and it might recover things" sort of method.

I recently did this with one of my Thinkpads, doing it during a battery firmware update among others. I wasn't successful in finding such a solution though. Where have you had success in finding some of the more obscure repair techniques?

[Syonyk]

It'll usually be listed in the BIOS upgrade guide. I've only ever seen the "weird recovery methods" on more performance-oriented mainboards - your RGB-heavy "gamer" boards tend to have some sort of recovery method. I don't know of any major OEMs who have such a thing. For a Thinkpad, though, I would wager good money that someone has directions out there for how to do it with a SPI flash clip - BIOS modding Thinkpads is pretty common, and most of the more intensive mods can't be done without an external writer.

[aspenmayer]

Thinkpads have a utility to make a BIOS recovery USB drive, which usually involves getting the BIOS update .exe file, possibly renaming it, then holding a certain key or key combination while turning the laptop on. You may need to use a special tool to format your USB drive to prepare it if it’s an older IBM Thinkpad. Sevenforums/Tenforums are decent message boards to learn about this kind of thing, as they usually have decent vetted tutorials with screenshots.