Hi Neal, thank you for your answer.... First of all, HWID is indeed 0754, i forgot to put it on my first message.

Now, i've followed your instructions with the sd card method and it didn't worked... the unit doesnt show "loader" word, resets right away and the content of the SD card remains untouched, no .bin files, no .log file

Kunix method seemed to have worked at first but and the end it didn't.
Extracted the boot.bin from 4.20 firmware, patched it, and made RGN, flashed in preboot with the SD card inserted only with Update.txt in folder Garmin\Updater\0754, and it stayed there for like half hour saying "LOADER" but never rebooted (i assume it should have done it as instructed on the txt), so i turned the unit off and checked the content of the SD card, same as above, no .bin files dumped, no .log file created.

SD card was on FAT32, but also tryied FAT with same results