Hmmm ... me to - look like i miss something. Well - i have at me Nuvi 12xx with damaged eMMC IC ( Loader ... freeze after try to cure it, due to erase / write process cannot be done ) - i was take out an working eMMC IC from Nuvi 200 ( with damaged PCB after bad charger ) - and voila - the Nuvi 12xx try to start - well now is time to bring it back to life due to different FW inside the eMMC IC cannot drive LCD, ect ... BUT ... there is BUT - at eMMC is stored different HW ID and Updater not work, also device ID will be different and paid lifetime maps updates will disappear .

There after reading seem i must make an empty SD card with :
root -
- Garmin ->
>-Updater->
>-0971-> ( due to the small beast 12xx was with 0971 HWID ) and inside will be
- ldr.bin ( renamed boot.bin extracted from nuvi12xx_GCDFile__620_971.gcd with RGN_Tool_V084 )
- Update.txt ( with needed comands )
- some more may be ?
and after this - put card in Nuvi 12xx and invoke an preboot mode.

Well - what a command set must be to erase current FW on eMMC, put new one, change HWID stored and original Device ID itself ?

Who can explain?

WBR, DebeliaMark, BG