GM ECU Shadow Password Calculator E39 / E39A / E98 / E84

[morfi]

I'd like to share a small tool I've put together: a browser-based calculator that derives the shadow password for several GM Delco ECUs directly from the markings on the module label/sticker.

Why?
If you brick an ECU and didn't back up the shadow region first, you're normally locked out. This recovers the shadow password from the label, so you can unlock the module for bootpin flashing and get it back.

Supported families
- E39 / E39A -> confirmed
- E98 -> matches every sample seen so far; a couple of digit values were never observed though
- E84 -> experimental; one password digit is uncertain

The algorithms are RE'd from known serial/password pairs so they may contain mistakes. I will keep improving them if I manage to get more known pairs.

Link to live website: https://gm-calculator.ext.io/ and source code.
note: the calculator runs fully offline in your browser.

[fl0wl0w]

Awesome work! Thank you for sharing!

[Tre-Cool]

nice work.

i have no need for it, but good to see stuff like this shared

[kostia111]

I see the hand of artificial intelligence.
In fact, the formula for E98 is much simpler if you look at the values ​​through human eyes.
Linear distribution
except for 20 values, which are adjusted for one condition (two bits are simultaneously set to one)
Therefore, this is most likely not your decision, but the work of artificial intelligence.

[morfi]

You could contribute the simpler formula. Alas, I can think of at least two reasons why that won't happen.

Did you notice, with your human eyes, that this thread is in "AI Developed tools" sub-forum?