I'm 99% sure, if we place the extracted firmware (*.bin) of an X10 in the SD card in the boot folder, it will reimage the firmware with the same image in the STM chip.

Same thing should apply to the GB.

Therefore if I get a X10 image with bin file in the boot folder and start up a GB with that SD card, it should reflash the STM chip with the coding of an X10 and in theory work.