My PRS650 has now the firmware version 1.0.00.14080. As far as I know this is the latest international version.
To convert my device I used a complete dump of a international device. The problem is that the device ID is coded somewhere in the flash and I don't know where. The result is now that 2 devices exits with the same ID.
To try to find out the block with device ID by changing one after each other back can result very fast in a bricked device. So this is also no solution. That is my problem.
Best regards from Japan,