It is flashed with FW for Nuvi 310, HWID 0566 , SW version 2.30.

I have backup of the device after the flash and before the format, and when i put back those files on the device, Webupdater then is recognizing it as Nuvi 310 and is offering update to version 5.20.
I realy do not know how to enter pre boot mode, so I can flash again the device with propper FW, the screen is white and now it has different display drivers.
I have tried by holding power button and after 10 - 30 s coneccting the device with PC, but updater does not see the device.
I hope SD card method can help.