X270 (20K5-S27L00) troubleshooting

[Chester Drawers]

Hi.

Can anyone recommend a next step here please?

Bought an X270 (20K5-S27L00) which completed POST but came supervisor password locked. My attempts to make the machine useable have not gone to plan.

1.Desoldered the 25Q128FVSQ BIOS and dumped a copy using a CH341, SOIC to DIP adaptor and Asprogrammer.
The CH341A is version 1.7 (selectable voltage) and I used a reasonable SOIC to DIP adaptor, not one of those high resistance leads with a clothes peg on the end...

2.Autopatched the BIOS and refitted to the motherboard.
On POST I was then greeted by a series of beeps which the Lenovo diagnostics (Android) app identified as “code 0285 TCG Compliant functionality error (might be TPM initialization failure)”.

3.Removed the BIOS for a second time and restored the original version. No change – same beep code on POST.

4.Removed BIOS for the third time and applied a clean ME version downloaded from here https://www.badcaps.net/forum/showth...t=70596&page=2 Also attached to this post. This proved to be a bad idea as I didn't check which revision of X270 board it was for.
Re-fitted BIOS to motherboard. No POST. Just the 3 flashes when the charger is connected. No beep codes. No backlight.

5.Removed BIOS for a fourth time. Restored original BIOS. Re-fitted to motherboard. Again, just LED flashes and fan initialization when connecting the charger. Pressing the power button spins the fan 3 times but that's it.

No physical damage to solder pads or PCB – worked with SMD for 27 years. Kapton covering up everything else. All 3 batteries disconnected whilst soldering.

Foolishly I only dumped one copy of the original BIOS. No excuses here.

Original, patched and clean ME versions attached to this post.

Thank you.

[reformatt]

Re: X270 (20K5-S27L00) troubleshooting

I think your original BIOS is ok as it opens fine in UEFI tool. The pre-reqs for the DXE injection patch are to

Disconnect the main and CMOS batteries until original BIOS is returned.
Remove any SSD if present.
Tape down anti-tamper switch if present.

The DXE injection hack alters the MEC firmware, because this is where the supervisor password is stored. At this point since you've returned your original BIOS and not working, I'd be checking the MEC firmware next. There are threads here how to do that via JTAG, but you'll need an appropriate programmer to do that (SVOD3 etc).

[Chester Drawers]

Re: X270 (20K5-S27L00) troubleshooting

Thanks for inspecting the upload and the constructive suggestions.

I can confirm that all 3 batteries were removed for the duration of my unsuccessful efforts and that the anti tamper switch was indeed taped down.

I'm away from workshop facilities for a few days, but will look into MEC firmware and report back on my return. I have access to a JTAG as they're used to program CPLDs at work.