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0175: Bad CRC1, Stop POST task ERROR --> SOLVED

Older ThinkPads from the 300, 500, 600, 700 Series, iSeries, Transnote etc.
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Franchute13
Posts: 44
Joined: Wed Aug 01, 2018 6:24 pm
Location: Buenos Aires, Argentina

0175: Bad CRC1, Stop POST task ERROR --> SOLVED

#1 Post by Franchute13 » Sat Dec 04, 2021 6:00 pm

Hello good.

Trying to fix problem 0175.
Searching in forums I found the following in Spanish:

https://es.linkedin.com/pulse/0175-bad- ... rez-arispe

The post says that by putting some cables in the parallel port it starts up, goes to DOS and applies an update to the BIOS and solves the problem.

Put the cables in the parallel port as follows:
14 - 11
15 - 9
16 - 12
17 - 13
20 - 25

The notebook starts up, it does not give the error 0175 but after a while it shuts down.

What I can be doing wrong?

Franchute13
Posts: 44
Joined: Wed Aug 01, 2018 6:24 pm
Location: Buenos Aires, Argentina

Re: 0175: Bad CRC1, Stop POST task ERROR --> SOLVED

#2 Post by Franchute13 » Sat Dec 04, 2021 10:10 pm

It is very easy to recover a machine with this error.

The following materials are required:
*One male DB25 plug for the parallel port.
*Cable
*A switch or jumper.
switch:
https://4.imimg.com/data4/HJ/QY/MY-3266 ... 50x250.jpg

jumper
https://www.profesionalreview.com/wp-co ... umpers.jpg

*A boot disk with the BIOS of the machine. It can be downloaded from the drivers page.
It does not matter that the battery does not work, the phlash command is used.
More info about the flash.
https://www.thinkwiki.org/wiki/Talk:BIOS_Upgrade

We build the circuit on the db25 connector by joining the pins
14 - 11
15 - 9
16 - 12
17 - 13
20 - 25 -> in the union of these put the switch or jumper.

We connect the dongle in the parallel port.
We short between 20 - 25 and while we do we turn on the notebook.
Release the switch / jumper when we see the screen with the IBM logo

Ready, the machine starts without problems.
Update the bios !!


Easy, fast and cheap !!.
I hope it works.

Tested on an A21m !!

solidpro
Senior Member
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Posts: 878
Joined: Thu Jun 11, 2020 11:46 am
Location: Milton Keynes, GB

Re: 0175: Bad CRC1, Stop POST task ERROR --> SOLVED

#3 Post by solidpro » Fri May 06, 2022 8:06 am

I had a T20 with the same issue - POST 0175: BAD CRC1, STOP POST TASK ERROR -

I can confirm the instructions below will SOLVE this issue. I took an old Parallel -> Centronics cable which had all 25 pins wired out. I used a continuity tester to find all the pin's wires below, and connected them together.

I then just touched the wires for 20/25 while powering on and basically it skips the CRC check.

I did find the T20 to be very picky about booting if it doesn't have a HDD/decent CR2032 battery to boot from and I used a dock to boot from a floppy but doing this parallel port wiring does indeed force the machine to skip the BIOS EEPROM CRC check so you can get beyond the message. I downloaded the BIOS from the drivers matrix and applied them using a floppy disk and problem solved!

I originally thought this was going to be a weird thing that worked for someone once in a specific scenario and I was wasting my time but actually turned out to be a great little hack which has saved another machine from landfill!

cheers
No longer using this forum due to lack of free speech.

Metrus
Posts: 1
Joined: Tue May 14, 2024 2:03 pm
Location: Berlin, Germany

Re: 0175: Bad CRC1, Stop POST task ERROR --> SOLVED

#4 Post by Metrus » Tue May 14, 2024 2:07 pm

Worked on a T20
this forum was a god sent
thanks guys <3

Macola
Posts: 1
Joined: Tue Jun 25, 2024 10:54 am
Location: Belgrade, Serbia

Re: 0175: Bad CRC1, Stop POST task ERROR --> SOLVED

#5 Post by Macola » Tue Jun 25, 2024 11:00 am

Hello All,

I successfully did the parallel port patch and both bios and ecp flash and my T23 is still giving me bad CRC1 fault when I remove the wires.

That seems quite odd as I was confident that flashing bios will make it go away. Any ideas?

SMA
Junior Member
Junior Member
Posts: 345
Joined: Fri Jun 29, 2007 3:48 pm
Location: Copenhagen, Denmark

Re: 0175: Bad CRC1, Stop POST task ERROR --> SOLVED

#6 Post by SMA » Fri Jun 28, 2024 3:19 am

This fix will only work for CRC1 0175 errors.
Start by checking, that what you have, is a CRC1 0175 error and not some other CRC1 error.

racecar56
Posts: 2
Joined: Sun Jul 05, 2015 2:40 am
Location: New Orleans, LA
Contact:

Re: 0175: Bad CRC1, Stop POST task ERROR --> SOLVED

#7 Post by racecar56 » Fri Jul 25, 2025 10:05 pm

Worked on my A21m, thank you!! I crammed a few paperclips into the parallel port in the specified pins, then used a pair of tweezers for 20>25 which I pulled out when the logo showed. Got a 'resource conflict' error followed by BIOS! With a new CR2032, it appears the computer is happy. Thanks!! Pretty cool that you can confuse it out of that error state by screwing with the parallel port to make it think something's there.

beshad
Sophomore Member
Posts: 136
Joined: Mon Aug 27, 2018 3:39 pm
Location: Christchurch, New Zealand

Re: 0175: Bad CRC1, Stop POST task ERROR --> SOLVED

#8 Post by beshad » Sat Sep 27, 2025 2:58 am

I followed the instructions and shorted the connections on the parallel port, which allowed me to bypass the 0175 error. I then used a bootable disk to start the system and ran the BIOS update, and that fixed the problem. Just to add, the 20–25 connection doesn’t need to be momentary, I kept all the wires connected the whole time and it worked fine. I also had to use flash2.exe from the BIOS disk with the /u flag to bypass the ThinkPad requirement for a fully charged battery.

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