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caps0ff / DecappingHelp

Help wanted tracker for decap project
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M5L8042 electronic read #1

Open caps0ff opened 4 years ago

caps0ff commented 4 years ago

The problem: M5L8042 is a popular microcontroller used in arcade games like Gladiator and vintage embedded devices like keyboards. Today they can be dumped by decapping and photographing the ROM (ex: https://forums.bannister.org/ubbthreads.php?ubb=showflat&Number=116721). This is very invasive and limits our throughput as well as raises concerns over damaging rare chips

The solution: We have some idea how to dump them electronically, but its unreliable. Take whats know and tune it to produce a stable algorithm

Skills required:

Datasheet: https://www.datasheets360.com/part/detail/m5l8042-xxxp/1808263372659743430/

Test procedure:

Note at around 2,064 bytes string “HI.A C.PROATII. 1.855”. This appears to be a garbled copyright string. Sample output with M5L8042-115P 708100

As you read multiple times the bytes are unstable and different valid bytes will appear. It might even be possible to dump a chip by doing this 10x and doing some sort of statistical analysis. But there are concerns it will over-voltage and damage the chip.

caps0ff commented 4 years ago

Update 2020-04-15: someone is looking into this. Might have an update in 2 weeks