Ok, guys, I think I figured out how to flash the ROM properly with MoVex.
(A)
connect the G710 (VDA GPS) by an appropriate USB cable to the PC
(B)
Press [Camera] + [POWER] on the G710 (VDA GPS) in order to go into download mode (the device is now ready to receive ROM updates)
(C) Windows registeres the device as properly connected USB device
(D) Start the flshing tool "Movex.exe"
(E)
Press [GET] and specify any name such as "test" or so and press [ENTER]
(F) repeat (E) 1 - 3 times
(G)
press [Browse] and select the ROM you want to flash into the G710 (VDA GPS)
(H) Movex immediately starts scanning the USB ports, finds the device and
begins flashing within max. of 3 seconds. Flashing takes no longer than 2 minutes.
(I) The device will be
automatically shutdown
(J) restart the device
(K) check whether or not you can access the Settings:
Start Settings and press the keys 1 and 6 to read the network settings. If this is successful, the ROM is good.
Good ROMs:
(01)
Teac's beta2-ROM (incl. accessories)
(02)
Ninjacul's ROM
Bad ROMs:
(01)
Teac's beta3-ROM
(02)
Powerbyte's Initial ROM (non-functional trackball)