Thinkpads Forum

Dear all,

I am trying to get a BIOS bricked P50 up and running, but am having issues connecting to the BIOS EEPROM chip while it is soldered to the motherboard. I prefer to flash the new BIOS in situ, as have neither soldering gear nor skills.

Others have successfully flashed a new BIOS on a P50 using a CH341A programmer and a SOIC-8 clip [1], both of which I have gotten. They work for reading the BIOS of my X220 using Flashrom.

I have tried and tried, but I cannot read the BIOS off the P50's chip. I have tried with different softwares (both CH341A Programmer and AsProgrammer in many versions, and Flashrom, all supporting the chip type), but they cannot identify the chip correctly, and give no or inconsistent readings. I have tried with and without the CMOS battery, and with and without PSU, with a new SOIC-8 clip, with pins unconnected and PSU connected cf. [2]

I am running the CHA341A v.17 programmer in 3.3 V mode in accordance with the specification of the Winbond W25Q128FV chip, and I have tried writing OP of [1] to hear what their configuration was, alas with no reply.

I have searched and searched, and come nowhere. I'm at the end of my wits.

So: Can someone offer suggestions for how I can read the BIOS off the chip in situ?

Any help or suggestions are highly appreciated.

[1]: https://www.win-raid.com/t7286f16-Probl ... #msg124756
[2]: https://www.partsnotincluded.com/flashi ... vo-laptop/

I don't know if this would help, but have you tried using shorter wires between the SOIC clip and the CH314?

CH341A green or black?
Maybe it needs 1.8V instead of 3.3V?
Proper Pomona 5250 clip?
There are various supposedly working software versions available: V1.4, V1.13, V1.18, V1.29, V1.30, V1.34, V1.38.

Thank you both for replies.

It is a green CH341A, version 1.7, which comes with a switch between 1.8, 2.5, 3.3 and 5 volts. Given the chip specifications, I've used it only in 3.3 V mode.

Is it safe to try 1.8V?

I use a Pomona 5250 clip, with 20cm cobber wires. I did not try with shorter wires as they work with the X220 (plus, the guy in the electronics store was quite sure they were very suited, but it won't rule anything out, as I know nothing).

I have tried several software versions, including V1.4, V1.13, V1.18, V1.29, and a customized versions of AsProgrammer 1.4 send from the Chinese seller of the programmer. None detect the chip, and all provide inconsistent readings. Flashrom sees the chip as "Generic EEPROM", for which reading is not supported.

AFAIK for Thinkpads you need the SER-version of the software.
I found (and used) a lot of info here: https://www.eevblog.com/forum/repair/ch ... upply-fix/
But that info may be too 'old' already if yours has a low-voltage-select switch.
Maybe that switch is not working properly, have you checked the output voltage?
If the voltage is not correct, maybe you have blown the chip already?
You can get pre-programmed new BIOS chips here: https://www.ebay.com/itm/383800793828

If you need more info about P50:
https://www.repairlap.com/threads/think ... -1-0.1056/
Requires joining first.
Assuming any Dane can read German:
https://thinkpad-forum.de/threads/p50-b ... rz.225110/