I have a Lenovo ideapad 720-15ikb (81c7) that seems to possibly have a bricked bios, the device will power on to a black screen spin up the fans for a few seconds and then just sit there with the caps lock light on and the keyboard backlight on.
I’ve finally got round to getting a ch341a programmer, done the 3.3v mod on it and have managed to read my bios off the chip, the issue I’m now faced with is that the file I extract from the chip contains all the intel ME stuff and the bios update file lenovo supply appears to just contain the uefi capsule.
Is there anyway to recreate the bin file with a bios that isn’t corrupted or does anyone have a backup of the same laptop that I could clear out the ME info and embed my laptops details into?
I have found one site that has a backup for the laptop but the site requested a “account upgrade purchase” in order for me to actually download the file, which I’m not overly keen on sending money to a site I haven’t heard of before.
Any knowledge or help on this would be much appreciated, the original bios corruption happened due to clearing the nvram a few too many times on my opencore hackintosh build for the laptop prior to the knowledge going round that clearing nvram on lenovo devices can end up corrupting the bios.
Please post a link to the dump you made or attach it here.
Here’s a link to download the dump, I’ve made two and verified both return the same hash bak1
Edit: Thought I should probably include a link to the bios update provided by lenovo BIOS Update for Windows 10 (64-bit) - 720-15IKB (Type 81C7) - Lenovo Support GB
Okay so an update on this and just as a note I don’t really have overly much clue on what I’m doing so I’m just winging it and would still appreciate some assistance still just to guide me on making sure I am still keeping key parts of my bios in tact.
I decided to have a go at completely wiping my vss2 store in my nvram region of the bios, I set all the values in the body of the vss2 store to 00, I wasn’t sure whether it was best to put it as FF or 00 but FF seems to look like padding to me and 00 seems to be what is used as free space, I could be wrong or just using the wrong words to describe how I interpreted it but that is what I assumed was the right option.
I then inserted the nvram volume back into a copy of my bios backup and verified it looked the same as the original except with an empty vss2 store using uefitoolNE.
I then proceeded to verify my bios chip again to make sure I still had a good connection and erased then wrote my modified bin.
I tried using Lenovos annoying pinhole button to access the “recovery” menu that lets me choose bios or boot menu, had the laptop reboot several times and then finally it showed a boot menu with the options to boot from network, no other options were present as I still have my nvme drive out as I can’t get the spi clip onto the chip is it is slightly in the way.
Good start I think but my question now is can I leave my vss2 store empty, although I assume some of it was restored when the laptop rebooted several times, or do I need to start re inserting some info from my bios backups?
I haven’t ever managed to load anything on the laptop since the corruption so there was definitely some corruption in my vss2 store
Well, looks like a valid dump, good. (A valid looking checksum isn’t 100% safe- in case bad contact of the clamp it’s possible to get 2 dumps completely FF without the CH341 complaining and with a nice looking identical checksum)
Static parts of the bios are a 100 % identical to stock bios region, so error might be in NVRAM. What did you do before the brick? Changed any settings, variables?
Machine specific data in first padding in bios region, oem avcivation in NVRAM:
OK began this post before you wrote your last post- first try would indeed be to empty NVRAM, FTW store and see what happens.
The NVRAM should look like the one in a stock bios which just contains the keys for secure boot- but they might get reconstructed, somtimes they are stored in other EFI volumes. NVRAM will normally get reconstructed, sometimes there’s machine specific information hidden there, but not in your case.
Since I don’t know precisely which area you FFed: Try to dump the firmware / bios region you have now to see what happened to it. Might use Intel ME tools 11 from here:
DOS command would be fpt -bios -d biosreg.bin, post the result.