Korg Electribe 2 white screen - no boot

unimetal · Post by **unimetal** » Tue Apr 13, 2021 5:25 pm

Hello everyone,

I got a broken/bricked Electribe 2.
If you press the power button for a short time the display backlight lights up for about a second and the display doesn't show anything. After the second the Korg turns off.
I tried both the batteries and the power jack (with laboratory power supply).
The previous owner said the bug came out of nowhere and told me to try a firmware upgrade. Of course this can't work if the display doesn't show anything, right?
I also opened the Korg and the flex cables and electronic parts seem to be (optically) fine.
I have an oscilloscope, multimeter and a laboratory power supply at my disposal to fix the problem.

Any ideas how to fix it?
Are service manuals available or block diagrams?
Are there typical parts which get broken?
Maybe there is a way to rewrite the EEPROM/Flash memory?

I made a Video to show the bug:
https://www.youtube.com/watch?v=67B1emGWuEg

Thank you in advance.

Best Regards
Simon

russellclarke · Post by **russellclarke** » Mon Apr 19, 2021 11:57 am

If it's a software fault you can probably fix it via JTAG. I use OpenOCD and a Raspberry Pi.

If the screen is lighting up, the secondary bootloader is probably fine but the application is corrupt. You should be able to halt the processor at 0xc0000000, load in the bytes from the firmware update file (minus 256 byte header), then continue. Once the app is loaded you can use the built in firmware update function to overwrite the application section of the flash memory.

The fact that it's turning itself off makes me think there could be a hardware issue (only because mine would hang instead of shutting down).

You might find you need a toggle switch soldered across the power button contacts to keep the power supply active. Switch it off again before the application finishes booting, or the unit will shut down again.

bujbot · Post by **bujbot** » Mon May 10, 2021 4:02 am

russellclarke wrote:If it's a software fault you can probably fix it via JTAG. I use OpenOCD and a Raspberry Pi.

If the screen is lighting up, the secondary bootloader is probably fine but the application is corrupt. You should be able to halt the processor at 0xc0000000, load in the bytes from the firmware update file (minus 256 byte header), then continue. Once the app is loaded you can use the built in firmware update function to overwrite the application section of the flash memory.

The fact that it's turning itself off makes me think there could be a hardware issue (only because mine would hang instead of shutting down).

You might find you need a toggle switch soldered across the power button contacts to keep the power supply active. Switch it off again before the application finishes booting, or the unit will shut down again.

Thanks Russellclark, can you provide a bit more information on how you halt the processor at 0xc0000000 and then load in the update file?

I've made progress on getting my bricked one back up. It now starts up and asks me for an update file off the SD card (but then it won't acknowledge the file on the SD card I've inserted). Sounds like your approach might help me through it.

Thanks!

russellclarke · Post by **russellclarke** » Mon May 10, 2021 1:13 pm

It now starts up and asks me for an update file off the SD card

If it gets this far you shouldn't need to do anything invasive. It will only see the file if it is at the correct path for the original factory model. It will only install the file if it is the latest firmware for the original factory model.

Assuming your e2 was originally a synth, you need SYSTEM.VSB (synth version 2.02) at

Code: Select all

KORG/electribe/System/SYSTEM.VSB

.

If everything is under an 'electribe sampler' directory, the synth will not see the files.

The only reason you would need JTAG from the stage you're at is if your SD reader is broken. You're better off learning that from the manual than from my limited understanding.

OpenOCD Manual:
http://www.openocd.org/doc/html/

Useful links:
https://iosoft.blog/2019/01/28/raspberry-pi-openocd/

https://learn.adafruit.com/programming- ... i/overview

Config files for OpenOCD:
https://github.com/bangcorrupt/hacktribe

bujbot · Post by **bujbot** » Mon May 10, 2021 2:34 pm

russellclarke wrote:
It now starts up and asks me for an update file off the SD card
If it gets this far you shouldn't need to do anything invasive. It will only see the file if it is at the correct path for the original factory model. It will only install the file if it is the latest firmware for the original factory model.

Assuming your e2 was originally a synth, you need SYSTEM.VSB (synth version 2.02) at
Code: Select all
KORG/electribe/System/SYSTEM.VSB
.

If everything is under an 'electribe sampler' directory, the synth will not see the files.

The only reason you would need JTAG from the stage you're at is if your SD reader is broken. You're better off learning that from the manual than from my limited understanding.

...

Thanks Russellclark,

Sorry, I should have been clearer with my situation when I responded. My electribe originally had the same failure in this thread (just the screen lighting up, nothing else) and through lots of experiments over JTAG with custom boot loaders I was able to get it to the point where it asks for the SD card. However, I cannot get it past that part and I've tried several Korg factory firmware options, even older ones.

My custom FW is a combination of what I pulled from the electribe bootloader itself and parts of firmware from the Korg website. For some reason I was only able to get this far with my frankenstien version of electribe workstation(synth) FW from the unit itself and Korg's website electribe sampler FW. When I use the Korg website FW for the workstation/synth and do the same thing, I cannot get this far. Mine is not the sampler and may be why I cannot get past this next step.

I'm thinking I would try the whole process again based on your comment above about stopping it at 0xc0000000 and loading in the correct FW from Korg. This idea was new to me but sounds promising!

russellclarke · Post by **russellclarke** » Mon May 10, 2021 3:02 pm

If I start OpenOCD and press the power button at the same time the processor halts in the bootloader, in internal RAM at 0x80nnnnnn.

Set a breakpoint at 0xc0000000 then resume and wait for it to halt.

Then load the latest firmware and wait for it to boot.

The first time the firmware boots it runs some updates and asks for a reboot. After this it might ask you for an update from the SD when you next boot. Use the latest firmware for the synth and it will write it to the flash.

Also, if you installed the latest Sampler firmware on a Synth, your synth knows it is a synth and is expecting synth firmware.