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BIOS for Toshiba T2100

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  • silence012
    replied
    I just checked pinout and they are the same. So definitely it can be replaced. I will test it, as many of Toshiba's old laptops uses this chip. Thanks modem7

    Leave a comment:


  • modem7
    replied
    Originally posted by silence012 View Post
    I didn't know that there is a cheap replacement 27C256 I paid 20EUR for original EPROM
    I got the information from someone who replaced the TC57256 in their Toshiba T1000. See the comment against the BIOS ROM in the photo at [here].

    Leave a comment:


  • silence012
    replied
    pavery
    I use simple command "fc.exe /b file1 file2" to compare two binary files but it is useful only if you have second file to compare with. We can try it with the bios dump I have, but it is different version.

    As modem7 mentioned, the best would be to burn these in into some chip and try. Send me your bin files on btrenkoski (at) penluchi.com and I will give it a try. I didn't know that there is a cheap replacement 27C256 I paid 20EUR for original EPROM

    Leave a comment:


  • modem7
    replied
    Originally posted by pavery View Post
    ... is there a way in Debug to show the first few bytes of the BIOS chip in hex and maybe the last few bytes?
    Yes. See [here] for an example of showing some bytes from address C800:0 (C8000) onward.

    Leave a comment:


  • pavery
    replied
    Thanks modem7. I'm just skeptical of the .BIN file created as whilst the directory shows it is 32KB in size, it took a whole lot of Retries and Ignores to get it saved down on to floppy. What I'm thinking is... is there a way in Debug to show the first few bytes of the BIOS chip in hex and maybe the last few bytes? The disk drives: while I'm familiar with 5.25" 360KB repairs, I've never worked on 3.5" Is it likely they just need a head clean & rails/mechanism cleaned/freed up?

    In any case I shall attempt to get a 3.5" drive fitted to my 98SE PC so I can get this .BIN file to you & Branko.

    Many thanks
    Philip

    Leave a comment:


  • modem7
    replied
    Originally posted by pavery View Post
    Thanks modem7. That appears to work. Is there a Debug command, or otherwise, by which I can verify I actually have the BIOS contents please?
    The photo in your post #12 shows that the motherboard BIOS chip is a Toshiba TC57256. Because I know that that can be replaced by a 27C256, I know that the BIOS chip is 32 KB in size. The motherboard BIOS normally resides at the end of the upper memory area, so for 32 KB, that corresponds to address range F8000 to FFFFF.

    If you post your MYF800.BIN, we can look at it, and make an educated opinion.

    The only real way to fully verify the content of MYF800.BIN would be to burn it to a 27C256 chip (speed rated at 200 ns [or faster] like your TC57256), then use that chip to replace your TC57256 chip.

    Leave a comment:


  • pavery
    replied
    Thanks modem7. That appears to work. Is there a Debug command, or otherwise, by which I can verify I actually have the BIOS contents please?
    Last edited by pavery; October 10, 2021, 11:32 PM. Reason: Added 'please'.

    Leave a comment:


  • modem7
    replied
    Originally posted by pavery View Post
    Hi Branko. You were going to double check that second Debug command. As it's written, I just get an error.
    Try changing the "FFFF" portion to "L8000".
    Last edited by modem7; October 8, 2021, 04:41 PM.

    Leave a comment:


  • pavery
    replied
    20211009_092914[1].jpg
    Hi Branko. You were going to double check that second Debug command. As it's written, I just get an error.
    Last edited by pavery; October 8, 2021, 12:34 PM. Reason: Added screen pic

    Leave a comment:


  • silence012
    replied
    Hey, that is pretty cool. This was version of BIOS in my original chip. Could you maybe send me "bin" file produced by first and second command?

    Leave a comment:


  • pavery
    replied
    The BIOS chip is located bellow keyboard middle-left.
    Just the info I was looking for as with the top lifted up but with the display still attached, it was easy to lift the keyboard & reveal the BIOS chip. See photo showing I have ver 4B:

    Philip

    20211003_174358[1].jpg

    Leave a comment:


  • silence012
    replied
    Hi Philip,

    In order to open it, you have to disassemble display first. I don't have Maintainence Manual for it, but yoi can download one for T3100 and the procedure is the same.
    Anyway, it is a little bit time consuming

    The BIOS chip is located bellow keyboard middle-left.

    If it is complicated for you, just do not open it..BIOS export will be enough...I can compare it with the one I have and see if it is different.

    For the BIOS export, second command should be ok, but I will double check. It should be address space between F800 and FFFF, so the last 32K from address space.

    When you export file...you should check it if it is only have FF in it, or different values. When I export file using first command it was exported successfully but all file was filled with FF.

    Good luck with FDDs

    Branko

    Leave a comment:


  • pavery
    replied
    OK, I've opened up my T2100 but... the display cabling is all shrink-wrapped shut. I don't really want to open all that up as there's a lot of it. Is there a way of glimpsing the BIOS chip without fully dismantling the machine? Where is the BIOS on the motherboard?

    I did the above Debug & the first variant worked fine & wrote a file to disk. The second declared an error at: -M F800:0 FFFF 0100. Shouldn't FFFF be 8000?

    My disk drives are flaky and it takes multiple attempts to get a write, but hopefully I'll get two files written, then I can see about reading them on a later PC & send them to you.

    Philip

    Leave a comment:


  • pavery
    replied
    Great that you got yourself a BIOS. I'll try this weekend to open up my T2100 & see what BIOS version I have.

    Philip

    Leave a comment:


  • silence012
    replied
    Hi Pavery,

    I managed to get BIOS dump, and burned it into chip. It is newer version then my was, but it did work This one is version 004C and it is probably dumped by some ROM reader.

    Anyway, I played little bit with DEBUG after that. Both commands are here:

    C:\> DEBUG
    -N MYF000.BIN (resulting file will be named MYF000.BIN)
    -R BX (set BX=0000H/CX=8000H as count of bytes to write, 00008000H = 32K)
    BX 0000
    :0000
    -R CX
    CX 0000
    :8000
    -M F000:0 8000 0100 (copy 32K bytes from F000:0 to offset 0100 in local segment)
    -W 0100 (write from offset 0100 in local segment)
    Writing 8000 bytes
    -Q


    C:\> DEBUG
    -N MYF800.BIN (resulting file will be named MYF000.BIN)
    -R BX (set BX=0000H/CX=8000H as count of bytes to write, 00008000H = 32K)
    BX 0000
    :0000
    -R CX
    CX 0000
    :8000
    -M F800:0 FFFF 0100 (copy 32K bytes from F800:0 to offset 0100 in local segment)
    -W 0100 (write from offset 0100 in local segment)
    Writing 8000 bytes
    -Q

    My T2100 has only one BIOS ROM. And content of BIOS rom is identical with export of second command (F800 - FFFF).

    I guess that first command is for other rom chip which I don't have. Also not sure what it would be...maybe some testing tools, etc.

    If you have time, you can try execute both commands and see how it looks like. Would be also good if you can open your computer and see which BIOS version do you have. It is on the sticker on top of BIOS chip.

    Cheers,
    Branko

    Leave a comment:

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