I'm still fighting with bricked PSR-S910 which became unusable after power off during update.
In short: I need someone who knows a bit more precisely about booting process - more than service manual. I've stopped at the "MAC address error" stage, but will try to re-programm BackupFlashROM chip (IC26) tomorrow, because I've just found a piece of MAC address in another S910's IC26. Desoldering & soldering back these chips is a nightmare So far I found out MAC address starts at position $0 (little-endian format) and rest of data I took from another S910's IC26, but it won't work - same error message as mentioned above. Tomorrow will try to add this partial MAC address found under $40 0000 (but original, bricked chip contains string "revision 1.1.0" here), but I'm not sure if that will work. Hence my question - anybody knows if there's any code available for IC26 that allows unbricking the keyboard ? Yamaha sells IC26 chips completely clean, so this is no way to simple buy chip and solve problem :/ Or maybe re-programming FlashROM Prog. (IC24, IC25) would help ?
Any help appreciated,
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