the idea was to DOWNGRADE or FORCE firmware update.
For QU-SB, this is the way :
1 - QU-SB switch OFF.
2 - Plug the USB Key with appropriate Firmware.
3 - Push and HOLD the FIRMWARE UPDATE Button
4 - Switch ON the QU-SB
5 - Release the Button and wait until the green light.
tips: watch the USB KEY Yellow LED, it should be ON and kind of blinking, showing some activities.
It should upload the firmware, whatever is the version…
I’ve tried many different flash drives.
Nothing helped.
I was already desperate and decided to sell the mixer for spare parts. But a Christmas miracle happened! )))
I saw an old flash drive “Lexar” in the store window and everything worked!
The latest firmware was installed into the mixer without any problems!