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Roland MPU-401 more ROM dumps and info

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First post, by mattw

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Maybe, interest reading for some of you:

https://github.com/schlae/mpu-imc/issues/1

but in any case the units with Serial numbers that were considered "undesirable" by the community, because of early firmware versions like 1.2 and whole articles were written where it's stated "Serial numbers above 588000 are safe":

http://nerdlypleasures.blogspot.com/2013/06/m … te-vintage.html

is not really true, because it turned out that there are early units which are real gems - those of them that were sent back to Roland for a repair and as result of that received an interesting update. Anyway, not to repeat myself all details I posted here:

https://github.com/schlae/mpu-imc/issues/1

for those of you that want to read it.

Reply 1 of 2, by Cloudschatze

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I've dumped MPU versions 1.3, 1.3A, 1.5A, and 1.5A_JMSC. The 1.5A version was found in an earlier, upgraded MPU-401, and matches the MAME dump. The (8KB) "JMSC" version was found in a couple of "tester" MPU-401 units.

Roland's integrated MPU-401 daughterboard, the RJA-401-HB, contains MPU version 1.5B, which, to my knowledge, remains undumped. The differences between 1.5A and 1.5B are yet unknown, but possibly just relate to the change from an HD6801 MCU to an HD6301.

Reply 2 of 2, by mattw

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Cloudschatze wrote on 2023-11-03, 20:22:

1.5A_JMSC

do you have CRC32 hash for that 1.5 versions? the 1.5 version I dumped from that repaired unit is still a mystery with its revision 0x39 number. it has CRC32 of "06510d91" - I believe it's 1.5 (not 'A') and they just put that strange revision to indicate either the repair or the FW port to the micro-controller chip in use.

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