Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

[samstown]

Hello,

I see two Gigadevice chip on motherboard but I am not sure if that could be the BIOS ROM.



Thanks
Sam

[samstown]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

Ok, I think found it.

Winbond 25Q16JWNIQ.

Following an update Laptop stopped booting. It start with black screen then stops, I guess it's BIOS issue.

[mon2]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

This flash chip is too low density to be the main bios chip.

Perhaps the bios chip for the local EC controller or wifi / ethernet interface.

The larger Gigadevice chips are probably the main bios flash ICs.

[samstown]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

And attached is what I read from the chip.Now I need to find another BIOS and try to flash it.

[samstown]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

This flash chip is too low density to be the main bios chip.

Perhaps the bios chip for the local EC controller or wifi / ethernet interface.

The larger Gigadevice chips are probably the main bios flash ICs.

Thank you. OK, then it will be more complicated to read.

[samstown]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

You read those with Pomona SOIC-Clip ? I 've tried a couple of time.. no communication. I have the chip in my reader DB so setup should be ok.

[mon2]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

No, the pomona clips (most are clones) are useless for this package.

From memory, believe this is the WSON-8 package. Please search for the datasheet for the device to confirm.

Then, you will need a flash memory breakout / dip conversion board. There is someone in the UK that sells a PCB to support this package but China has clones that should be also ok. In a nutshell, you want to hot air off this flash device -> solder onto another PCB that should offer a DIP (through hole pins) conversion. Then you can R/W/E the flash device.

Be sure to review all details before purchasing / proceeding. This and other forums should mention the full details of this bios device.

[samstown]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

Thank you for the details then I will give up. The PC still under warranty, customer should return it to Lenovo if there is no other option than heat gun to flash it.

[mon2]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

This is the guy with assorted tools. The PCB to DIP is a very simple design but not too many boards out there - Aliexpress has a few.

https://www.cmizapper.com/index.html

Something like this but is from a quick search (not 100% sure if your package is the same size - there are many variations in the marketplace):

https://www.aliexpress.com/item/1005...d=0oXdO1X2cs4u

The real pain is that the zero force sockets are $$$ for the real deal. These are hacked sockets but can work for low volume. I recall having chats with a zero force socket manufacturer and in high volume, they wanted ~$40 USD each. The investment for just the socket MOQ would be more than my car. No thanks.

[samstown]

Re: Where is BIOS Chip on Thinkpad Gen1 P4 - Model 20Y4S04W00

Thank you. I'll see if I can get one of those for test.