Friday, December 21, 2007

Reset BIOS password on an IBM Thinkpad T23

I had really hoped I could reset the supervisor password on a spare IBM T23 laptop we had around the office by - disconnecting the CMOS battery or shorting a jumper. Anything besides the procedure described on

But apparently there's no way to "reset it" you just have to build yourself a "testpoint" jig and read the encrypted data directly off the EEPROM connected to the main board.

So I picked up a few parts from RadioShack and went to work. BTW, The password turned out to be XPBIOS.

But, I feel it's important to note, I'm an idiot.

The image you see above here is NOT of a working cable. It is in-fact the improperly constructed cable which was later rebuilt and used to successfully dump the contents of the actmel eeprom on the IBM Thinkpad.

Apparently there isn't much standardization to diagramming a serial connector. It's hard to tell if the flat picture you're looking at is supposed to be a male or female connection. And even worse - true circuit diagrams will often show the BACK of the connector - i.e. they draw it so you would be looking at where the "wires" are ACTUALLY connecting to the BACK of the connector.


Your only real hope is to know the pin numbers of an rs232 cable. Thankfully, almost ALL diagrams will include pin numbers to specify the orientation of the connector and avoid this type of confusion.

Well... that doesn't help you much if you don't know which pin is which on your cable. So here is a picture of an rs232 / db9 / 9-pin serial cable - with both male and female connectors labeled pin 1, pin 5, pin 6, and pin 9.

Not even wiki has this kind of information...

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