Unbrick Yamaha A4000 and A5000 Samplers



The A4000 and A5000 are the last hardware samplers produced by Yamaha in 1999. They're pretty sturdy but it's not impossible to brick them, specially when messing around with their IDE and SCSI internals, or accidentally shorting things. This can lead to a corrupted OS and unbootable sampler. There is however a completely undocumented feature that allows to flash the OS via MIDI/SysEx, thanks to booting into a small software that's in a ROM somewhere and that will start listen to whatever arrives on the MIDI IN-A port.

This info, and the SysEx version of the firmware, is not even in the rather extensive service manual. My guess is that its existence eventually leaked into the community from people working in Yamaha service centers and who realized that many returned bricked/b0rked A4000/A5000 could be revived like this, and it was simpler to give the info as a first try, as opposed to go through a full RMA. At time of writing, there is only one private forum that mentions this trick, and only one site left that has a copy of the MIDI files needed. I'm putting it all here, to duplicate this specific and scarce info.

The overall process is done in two steps because only an old firmware exists as MIDI file: so 1. we update to 1.07 via MIDI, and 2. we update to latest 1.50 via floppy.

All the files needed are in the archive.

Update to 1.07 via MIDI
aplaymidi --port 20 main.mid # you can find the right port with aconnect -l aplaymidi --port 20 sub.mid
 * Plug the MIDI out of your soundcard into the MIDI IN-A of the sampler
 * Enter the  by turning on the sampler while holding the three buttons ,   and
 * On your computer, playback the  file
 * When no more  are received and the line   is displayed, then the update is finished.
 * If you have an A4000, you can reboot, no need to do anything else. Unbricked!
 * If you have an A5000, you need to update the secondary CPU firmware, reboot into the, and playback the   file
 * When no more  are received and the line   is displayed, then the update is finish. Your A5000 can be rebooted. Unbricked!

Update to 1.50 via floppies

 * If you have an A4000 you need one floppy, if you have an A5000 you need two.
 * Format them with an MS-DOS filesystem and copy the following files:
 * A4000:
 * A5000:  and
 * Insert the floppy with  in the sampler
 * Press, then
 * Select  and press
 * Select, the sampler will scan the floppy drive and if it finds the right file it will display
 * Press  and follow the instructions, the process is over when all the function key LEDs are on.
 * If you have an A4000, you can reboot, no need to do anything else. All done!
 * If you have an A5000, you need to follow the same steps again with the floppy containing, and this time selecting  . Once everything is flashed, you can reboot, no need to do anything else. All done!