Service Forum

[steve6386]

Hi,
If I had a corruted bios on a T40 and wanted to remove it chip to reprogram it..which chip do i need to program, the M50FW080 ? And why exactly are there two different chips ?
Cheers
Steve.

[steve6386]

Victor,
I removed the chip, reprogrammed (Willem) it with the bios file from the thinkpad diskette .FL1 but it still doesnt want to boot. Any ideas, maybe Ive missed something or maybe I have other problems too?
Cheers
Steve.

[bob]

Doesn't want to boot or it just doesn't want to do the POST?

It is something shown there on the screen?

[steve6386]

Hi Bob,
Doesnt want to post, blank screen. seems to check the cd drive but nothing more. I have tried 2 bios versions newest and oldest to see if it could be the embeded controller version, still nothing.
Cheers
Steve.

[steve6386]

Bob
I have been starting programming the chip at offset 0h, is that correct ? do I also have to program the embeded controller to the same chip ?
Cheers
Steve.

[victor]

I think you overwrote the boot block. Find another PC and try to copy the prom's original content.
You can do that without unsoldering, by using some software like Uniflash. In fact you need to save the original BIOS including the boot block, then to write using Willem.

[steve6386]

Victor,
Can I use bios from another type of thinkpad for the T40 eg I have made dumps of both boot block and whole bios of A31.
Cheers
Steve.

[steve6386]

Victor,
I am wondering if I write the boot block only to the chip at 0f0000h which is where it memory map of chip says is for boot block would this be compatable from A31 and allow me to then update the whole bios from a floppy ?
Cheers
Steve.

[victor]

Normally, the boot block works if you copy the one from the same kind of chip. Give it a try...

[steve6386]

Victor,
Both the A31 and the T40 use the same chip M50FW080 so I programmed the boot block from the A31 to the same address on the T40 0FE000h, no luck. Are you saying that the boot block on all M50FW080 is identical no matter what type thinkpad ?
Cheers
Steve.

[steve6386]

Victor,
I dont supose you have a dump from a T40 I could try ?
Cheers
Steve.

[victor]

Usually the boot block is the last block. M50FW080 has no specially boot block area like other FWRs, I guess I had SST in mind, which have a special area for BB.

M50FW080 is a contiguos PROM, all areas are the same, every block can be protected separatelly. You just need to find a T40 and dump the BIOS, then write it into the damaged chip, including the boot area.
I used several times Uniflash and the so called hot flash method, which consists in replacing the working BIOS chip, while the PC is still on with the chip you want to write (The BIOS is really needed only at start-up, in rest the PC is using a copy of it into the main RAM), and flashin the code using Uniflash.
Of course you can do the same with willem, but Uniflash is made to detect the chip type and help you by automatically arraging the offsets, writing the BB by the chip type, etc. It was very convenient.

One question, after you programed the chip, you have also to update the embedded controller FW, but anyway the laptop might POST even without that. Are you sure you resoldered the chip properly?

I don't have a T40 back-up, unfortunatelly (or not), all my machines here are newer than T40, but I will ask somebody to save the code. You need a full copy of another T40 FW Rom, byte by byte.

[steve6386]

Victor,
Im as sure as i can be that its in there ok, but as I said it was just the boot block from an A31 that I programmed it with to try it.
you said "you have also to update the embedded controller FW, but anyway the laptop might POST even without that."
How do i do that if it wont post ?
Cheers
Steve.

[steve6386]

Victor,
Dont worry about it, I sorted it.
Cheers
Steve.