Toshiba notebook BIOS password backdoor


I've had a couple of requests for more information. Here's photos of how I did it.

Tosh Plug from the end of an old parallel cable

Tosh Disassembled plug. Screws can be discarded.

Tosh Back of DB25 after opening assembly

Tosh Example of three-wire join before soldering.

Tosh Shield Cable - not used

Tosh Soldered connections, taped for insulation

Tosh Wires folded safely inside plug assembly

Tosh Reassembled plug, ready to use.

This method works on ancient models (386 and 486 vintage probably.)
This is what you need:

1. Your notebook
2. An empty formatted diskette (720 kb or 1,44 mb)
3. A second computer (e.g. a DOS desktop PC)
4. A hex-editor (e.g. Norton DiskEdit or HexWorks)

This is what you have to do:

1. Start the desktop PC and start the hex-editor
2. Put the disk in drive A:
3. Change the first five bytes of sector 2 (boot sector is sector 1) to: 4B 45 59 00 00
4. Save it! Now you have a KEYDISK
5. Remove the disk from drive A:
6. Put the disk in the notebook drive
7. Start the notebook in Boot Mode (push the reset button)
8. Press Enter when asked for Password:
9. You will be asked to Set Password again. Press Y and Enter.
10. You now see the BIOS configuration where you can set a new password.

Of course this will only work if you can still boot the machine. And that's all!

 Newer Models (pentium class vintave, possibly up to PII)

Toshiba notebook BIOS password removal via Parallel Port

If you make a simple device that you connect to your parallel port, a lot of Toshiba computers remove the password when you boot it up. The device, named "loopback" by some, could be made out of any parallel wire with 25pins connectors. You should connect these pins:


For those who care, what is connect to what

1-5-10,   1=Strob, 5 =data bit 3, 10 = ack
2-11,      2=data bit 0, 11=Busy
3-17,      3=data bit 1, 17=SLCT IN
4-12,      4=data bit 2, 12=Paper End
6-16,      6=data bit 4, 16=reset
7-13,      7=data bit 5, 13=SLCT (out)
8-14,      8=data bit 6, 14=Auto feed
9-15       9=data bit 7, n/c sometimes +5v

Strobe is an output, tell the printer when data is ready.
ACK is an input tell computer when printer has read the port.

All other pins can be program as input or outputs.
Except 15.

Printer Computer port
1 Strobe
2 Data bit 0
3 Data bit 1
4 Data bit 2
5 Data bit 3
6 Data bit 4
7 Data bit 5
8 Data bit 6
9 Data bit 7
10 ACK
11 Busy
12 Paper End
13 SLCT (out)
14 Auto feed
15  n/c sometimes +5v
16 Reset

Rest 18-25 Gnd

Newest Toshiba Laptops

If you have a newer laptop again, one without a parallel port you will need a special USB password removal tool, and they cost much more. Try ebay and see what you find.

This file last modified Friday February 25, 2005

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