Possible? Sure. Practical and does anyone have the time or inclination, probably not. If you’re offering, go for it and please share. There will be a few people who will be grateful for your effort.

mikeyp wrote on 2022-06-21, 16:28:

Possible? Sure. Practical and does anyone have the time or inclination, probably not. If you’re offering, go for it and please share. There will be a few people who will be grateful for your effort.

I have only extracted the bios, placed a socket to be able to reinstall it on the motherboard and I have read the flash memory to get its porogram. I don't know if it can be uploaded to the forum...

I just don't know how to modify it... but if someone helps me I'll do the necessary tests to put everything in the 386 and check if it works. I would be happy to post it here to help the community.
If someone wants to see the bios with a hexadecimal editor I can send it to them by email or tell me how to publish it in the forum.
Kind regards from Spain
My e-mail z7upower@yahoo.es

The T2000sx BIOS unfortunately doesn't work in PCem. If someone could get it (or one of these other BIOSes) to run in PCem or similar, I'd be more interested in looking at this as I don't have any of the hardware. At https://github.com/biketronic/T2000SXe-BIOS the author figured out the ATA IDENTIFY check, which I also was looking at in the BIOS image, but I have no idea how he figured out the SETUP program to unlock the ability to flip between drives.

mikeyp wrote on 2022-02-06, 23:17:

You’re missing the point. Please read the whole thread before replying. The issue is that these laptops only allow the specific models whitelisted in the bios. Ergo we need to fake this ID in the firmware of the drive connected or the bios will reject it and merely say no drive connected.

TronadaSport wrote on 2022-06-21, 19:31:

I have only extracted the bios, placed a socket to be able to reinstall it on the motherboard and I have read the flash memory t […]
Show full quote

I have only extracted the bios, placed a socket to be able to reinstall it on the motherboard and I have read the flash memory to get its porogram. I don't know if it can be uploaded to the forum...

I just don't know how to modify it... but if someone helps me I'll do the necessary tests to put everything in the 386 and check if it works. I would be happy to post it here to help the community.
If someone wants to see the bios with a hexadecimal editor I can send it to them by email or tell me how to publish it in the forum.
Kind regards from Spain
My e-mail z7upower@yahoo.es

Could one of you who has dumped the BIOS post it? I think I see how to fix the T1800/T1850 BIOSes but I have no real Toshiba hardware to test on.

Let's see if you can download the bios from here, if someone knows how to upload it directly to the forum, do it.

https://drive.google.com/file/d/17oBbn39YTnjy … iew?usp=sharing

If you have progress or want to try the modified bios send it back to me: z7upower@yahoo.es

TronadaSport wrote on 2022-06-27, 16:05:

Let's see if you can download the bios from here, if someone knows how to upload it directly to the forum, do it.

https://drive.google.com/file/d/17oBbn39YTnjy … iew?usp=sharing

If you have progress or want to try the modified bios send it back to me: z7upower@yahoo.es

I also have the same problem with T1850, both FDD and HDD are dead (FDD could be fixed with new belt) and after spending 2 days with various CF cards, I stumbled on this forum 😀
I am eagerly looking forward to any progress here...
Regards, Bojan

Bojan wrote on 2023-02-06, 01:50:

I also have the same problem with T1850, both FDD and HDD are dead (FDD could be fixed with new belt) and after spending 2 days […]
Show full quote

TronadaSport wrote on 2022-06-27, 16:05:

Let's see if you can download the bios from here, if someone knows how to upload it directly to the forum, do it.

https://drive.google.com/file/d/17oBbn39YTnjy … iew?usp=sharing

If you have progress or want to try the modified bios send it back to me: z7upower@yahoo.es

I also have the same problem with T1850, both FDD and HDD are dead (FDD could be fixed with new belt) and after spending 2 days with various CF cards, I stumbled on this forum 😀
I am eagerly looking forward to any progress here...
Regards, Bojan

I think I have a T1850 BIOS ready to go that accepts all drives as 1024/16/63, but couldn't find anyone to test it. The issue is if it doesn't work, it will brick your system, and I believe these have soldered-in BIOS chips so you would need a hardware solution at that point.

jakethompson1 wrote on 2023-02-08, 23:15:

I think I have a T1850 BIOS ready to go that accepts all drives as 1024/16/63, but couldn't find anyone to test it. The issue is if it doesn't work, it will brick your system, and I believe these have soldered-in BIOS chips so you would need a hardware solution at that point.

I haven’t forgotten. Just don’t have the time sadly to be disassembling the machine to get a working floppy drive hooked up or if it fails, getting out the hot air soldering stuff and removing the chip.

Any news?
If someone send me modified BIOS, I may find a courage to attempt to remove EEPROM and reprogram it.

I had modified the BIOS of my T3100SX to replace the parameters of an hardcoded HDD with the ones from a CF card, here's the post I had made Toshiba T3100SX Modified BIOS / Help with its IDE

In that T1850 binary the HDD parameters start at offset 0x84E8 and it seems to be only one set (so no "alternate" like in my T3100SX). The first is CP2044:

6702 04 0000FFFF0000000000 6702 11 07

615 cylinders (0x0267), 4 heads, landing zone 615, 17 sectors (0x11)

I don't know what that last byte is/means.

This is the entire HDD table matched as best as I could:

1CP2024:		6702 04 0000FFFF0000000000 6702 11 07
2JD-E2825P:	4502 02 0000FFFF0000000000 4502 24 07
3CP2044:		D403 05 0000FFFF0000000000 D403 11 04
4JD-E2850P	1703 03 0000FFFF0000000000 1703 23 07
5CP2034:		9B01 04 0000FFFF0000000000 9B01 26 04
6CP2064:		3703 04 0000FFFF0000000000 3703 26 04
7MK1122FC:	DC03 05 0000FFFF0000000000 DC03 11 04
8??????????:	6702 10 0000FFFF0000000000 6702 11 07
9MK2024FC:	DC03 0A 0000FFFF0000000000 DC03 11 04
10CP2088 (?):	2502 08 0000FFFF0000000000 2502 26 04
11CP2124:		FA02 08 0000FFFF0000000000 FA02 27 04
12MK2124FC:	A603 10 0000FFFF0000000000 A603 11 04
13WD AB140:	D403 05 0000FFFF0000000000 D403 11 04
14WD AH260:	0004 07 0000FFFF0000000000 0004 11 04
15WD AH280:	D403 0A 0000FFFF0000000000 D403 11 04
16CP2084:		2402 08 0000FFFF0000000000 2402 26 04
17JD-E2130M:	1A02 08 0000FFFF0000000000 1A02 3B 04

To add support for a CF card get its CHS parameters, translate them to hex to match and replace an existing drive with those. Then adjust the corresponding strings for name (around 0x888A) and capacity (around 0x375E) to match the CF card (don't exceed the preexisting number of bytes for either), fix the checksum and voilà.

Other IDE Toshiba laptops (for example T1200XE) have the parameters encoded the same way and are very easy to find and the same procedure applies

Hi,

Which algorithm did you use to calculate checksum? And against which value in the ROM you compared?

Thanks,
Branko

Hi everyone!
Look what I found: "If you have a BIOS version below 3.50 then your system will only accept 2.5" disk drives that are specified in the BIOS. Version 3.50 however sends a command to the harddisk to report its geometry and then the BIOS will adapt itself. As a result it recognizes all possible 2.5" IDE drives."
Source: http://www.euronet.nl/users/ernstoud/upgrade.html
Does anyone tried this? Where is possible to downlad the 3.5 bios ?

xjr358 wrote on 2024-10-27, 07:09:

Hi everyone! Look what I found: "If you have a BIOS version below 3.50 then your system will only accept 2.5" disk drives that a […]
Show full quote

Hi everyone!
Look what I found: "If you have a BIOS version below 3.50 then your system will only accept 2.5" disk drives that are specified in the BIOS. Version 3.50 however sends a command to the harddisk to report its geometry and then the BIOS will adapt itself. As a result it recognizes all possible 2.5" IDE drives."
Source: http://www.euronet.nl/users/ernstoud/upgrade.html
Does anyone tried this? Where is possible to downlad the 3.5 bios ?

Good news for you, I finally got a Toshiba T4400C with the 3.50 bios - all my other ones have 3.20 bios. The 3.50 BIOS works with a 256MB compact flash without any issues, which is great because the laptop that I got with the 3.50 BIOS has a broken hard drive from capacitor leakage.

I just found that you can check which version of the BIOS you have either using the toshiba bios version utility or the Microsoft Diagnostics (msd) utility in DOS, in the 'Computer' section. My 3.50 BIOS chip has "7136" on the label, while all the 3.20 BIOS chips have "7118" on the label.
There appear to be at least three 1mbit SOP32 ROMs used and I think I know why everyone goes quiet when asked about BIOS updates.
toshiba tc541000af-15
hitachi hn27c101afp-12
nec upd27c1001agw-12

They all appear to be one time programmable ROM chips so upgrading the BIOS requires swapping out the chip for one programmed with the later BIOS. That's why the T4400 has an easy access cover to access the BIOS and why it's so easily removable rather than being soldered down.
When I say easily removable, be very careful if you try to. Refer to section "4.14 The BIOS ROM" in the T4400SXC maintenance manual to see how to remove it properly and safely, trying to remove it another way may break the black plastic clip which is irreplaceable. (On an NEC laptop with a similar clip, I forced the clip off the wrong way and broke it, had to solder down the BIOS chip to make the laptop operable again)

I've found a promising lead on what appears to be a functionally identical and more available replacement - the MX27C1000MC-12.

I'm gonna see if I can get an adapter for SOP32 chips for my TL866 so I can read out and write new copies of this 3.50 BIOS

Thermalwrong wrote on 2025-02-16, 01:28:

Good news for you, I finally got a Toshiba T4400C with the 3.50 bios - all my other ones have 3.20 bios. The 3.50 BIOS works wit […]
Show full quote

xjr358 wrote on 2024-10-27, 07:09:

Hi everyone! Look what I found: "If you have a BIOS version below 3.50 then your system will only accept 2.5" disk drives that a […]
Show full quote

Hi everyone!
Look what I found: "If you have a BIOS version below 3.50 then your system will only accept 2.5" disk drives that are specified in the BIOS. Version 3.50 however sends a command to the harddisk to report its geometry and then the BIOS will adapt itself. As a result it recognizes all possible 2.5" IDE drives."
Source: http://www.euronet.nl/users/ernstoud/upgrade.html
Does anyone tried this? Where is possible to downlad the 3.5 bios ?

Good news for you, I finally got a Toshiba T4400C with the 3.50 bios - all my other ones have 3.20 bios. The 3.50 BIOS works with a 256MB compact flash without any issues, which is great because the laptop that I got with the 3.50 BIOS has a broken hard drive from capacitor leakage.

I just found that you can check which version of the BIOS you have either using the toshiba bios version utility or the Microsoft Diagnostics (msd) utility in DOS, in the 'Computer' section. My 3.50 BIOS chip has "7136" on the label, while all the 3.20 BIOS chips have "7118" on the label.
There appear to be at least three 1mbit SOP32 ROMs used and I think I know why everyone goes quiet when asked about BIOS updates.
toshiba tc541000af-15
hitachi hn27c101afp-12
nec upd27c1001agw-12

They all appear to be one time programmable ROM chips so upgrading the BIOS requires swapping out the chip for one programmed with the later BIOS. That's why the T4400 has an easy access cover to access the BIOS and why it's so easily removable rather than being soldered down.
When I say easily removable, be very careful if you try to. Refer to section "4.14 The BIOS ROM" in the T4400SXC maintenance manual to see how to remove it properly and safely, trying to remove it another way may break the black plastic clip which is irreplaceable. (On an NEC laptop with a similar clip, I forced the clip off the wrong way and broke it, had to solder down the BIOS chip to make the laptop operable again)

I've found a promising lead on what appears to be a functionally identical and more available replacement - the MX27C1000MC-12.

I'm gonna see if I can get an adapter for SOP32 chips for my TL866 so I can read out and write new copies of this 3.50 BIOS

Hi! Great job, thanks for sharing! What I've found that my T4400SX (b/w lcd) has a maximum v 2.2 BIOS which it currently has and no luck with 512CF card 🙁 Maybe I should try 256Mb card, the BIOS has only 40 and 80 mb options though. So my only way is to try to modify the BIOS of the SD to mini IDE adapter by changing its the name as described by @notebookkiller
Please let us know if you succeeded with SOP32 adapter for TL866, I haven't found one for reasonable price.

xjr358 wrote on 2025-02-16, 02:10:

Thermalwrong wrote on 2025-02-16, 01:28:

Good news for you, I finally got a Toshiba T4400C with the 3.50 bios - all my other ones have 3.20 bios. The 3.50 BIOS works wit […]
Show full quote

xjr358 wrote on 2024-10-27, 07:09:

Hi everyone! Look what I found: "If you have a BIOS version below 3.50 then your system will only accept 2.5" disk drives that a […]
Show full quote

Hi everyone!
Look what I found: "If you have a BIOS version below 3.50 then your system will only accept 2.5" disk drives that are specified in the BIOS. Version 3.50 however sends a command to the harddisk to report its geometry and then the BIOS will adapt itself. As a result it recognizes all possible 2.5" IDE drives."
Source: http://www.euronet.nl/users/ernstoud/upgrade.html
Does anyone tried this? Where is possible to downlad the 3.5 bios ?

Good news for you, I finally got a Toshiba T4400C with the 3.50 bios - all my other ones have 3.20 bios. The 3.50 BIOS works with a 256MB compact flash without any issues, which is great because the laptop that I got with the 3.50 BIOS has a broken hard drive from capacitor leakage.

I just found that you can check which version of the BIOS you have either using the toshiba bios version utility or the Microsoft Diagnostics (msd) utility in DOS, in the 'Computer' section. My 3.50 BIOS chip has "7136" on the label, while all the 3.20 BIOS chips have "7118" on the label.
There appear to be at least three 1mbit SOP32 ROMs used and I think I know why everyone goes quiet when asked about BIOS updates.
toshiba tc541000af-15
hitachi hn27c101afp-12
nec upd27c1001agw-12

They all appear to be one time programmable ROM chips so upgrading the BIOS requires swapping out the chip for one programmed with the later BIOS. That's why the T4400 has an easy access cover to access the BIOS and why it's so easily removable rather than being soldered down.
When I say easily removable, be very careful if you try to. Refer to section "4.14 The BIOS ROM" in the T4400SXC maintenance manual to see how to remove it properly and safely, trying to remove it another way may break the black plastic clip which is irreplaceable. (On an NEC laptop with a similar clip, I forced the clip off the wrong way and broke it, had to solder down the BIOS chip to make the laptop operable again)

I've found a promising lead on what appears to be a functionally identical and more available replacement - the MX27C1000MC-12.

I'm gonna see if I can get an adapter for SOP32 chips for my TL866 so I can read out and write new copies of this 3.50 BIOS

Hi! Great job, thanks for sharing! What I've found that my T4400SX (b/w lcd) has a maximum v 2.2 BIOS which it currently has and no luck with 512CF card 🙁 Maybe I should try 256Mb card, the BIOS has only 40 and 80 mb options though. So my only way is to try to modify the BIOS of the SD to mini IDE adapter by changing its the name as described by @notebookkiller
Please let us know if you succeeded with SOP32 adapter for TL866, I haven't found one for reasonable price.

You can get a SOP44 to DIP44 adapter which is 1:1 so you can trim off the 4 pins at the end to make it a DIP40 adapter for the TL866. I didn't realise you could get them for something like £6 from china, but this was available immediately:

Took over an hour to make so the SOP44 to DIP44 adapter is pretty cheap, especially if you don't already have a SOP32 clip available from a broken T4400 board. The pin spacing of the SOP chips is 1.27mm so it was okay for me to grind off the copper of a single 2.54mm pin hole to make 2x1.27mm pads. Also the SOP32 clip was removed from a dead T4400C mainboard with low melt solder - I didn't wick all the low melt solder off on the legs so I couldn't get any wires to stick until that low melt solder was cleaned off better.

And it has worked, the T4400C / T4400SXC 3.20 and 3.50 BIOS chips are both dumped:

3.50 has been written to 5x Macronix 27c1000MC-12, which ironically was the only chip of this type that my TL866 knows how to read / program, so the Toshiba TC541000A was read as a 27C1000MC with the "Check ID" option disabled. Writing a One Time Programmable chip is a real nail biter and failed the first time. It seemed the VPP wire with its 12.5v was too close to a neighbouring pin and it failed cos of that, but the second time it programmed fine and no bad chips so far.

The 3.50 BIOS has been tested on my current favourite T4400C that the 3.50 BIOS (label 7136) came from originally and the new BIOS chip works just fine in it so far as booting up DOS and detecting a CF card without issue. It probably shadows the BIOS into RAM so if it gets that far it should be 100% compatible. The speeds and voltages all match up so it should be fine.

I suspect you've seen it but the EMIS archive hosted by conventionalmemories lists the different BIOS version for the T4400 series: https://conventionalmemories.com/EMIS/emis1voy.htm

T4400SXC
V3.10 7106 7106.ZIP Apr-92
V3.20 7118 7118.ZIP May-92
V3.50 7136 7136.ZIP Feb-93 HDD 320MB

T4400SX /L /P
V1.20 1163 -- Jan-92 first
V2.00 7103 -- Mar-92 new HDD support
V2.10 7105 7105.ZIP Apr-92 HDD recognition
V2.20 7117 7117.ZIP May-92 VRAM problem

Look at how the bios versions and what I suspect are build numbers line up - the T4400SX has bios build 7117 and the T4400C has build 7118, but the T4400SX didn't get a corresponding build 7135. I wonder if we could do like I did with my AST Bravo NB: Re: AST Bravo NB 4/25s Laptop - Quanta LK4 - HFSLK4 - where the VBIOS is in the first half of the flash chip and the system BIOS in the latter half, put the mono vbios onto the 3.50 bios and would that work? I can't test that as I don't have a T4400SX yet 😀
If that couldn't work, there's someone on the VCFED forums that's reverse engineered the BIOS for the 430CDT (PCI chipset Pentium) to enable support for drives up to 32GB (was 8.4GB previously): https://forum.vcfed.org/index.php?threads/90s … eering.1250653/ Perhaps they would know how to patch in autodetect from the 3.50 bios or maybe even LBA support, or at least how to fix the BIOS checksum if we need to move over specific bits of the BIOS to get autodetect working on the T4400SX.