First of all, thanks for reply.

Clear boot data -> With device not conected anywhere, I press at the right bottom of the screen (usually this do a reset factory defaults but no message on screen to clear data, device reboots)
I have an RGN firmware file backup. (I created this file several years ago to unproted my device and use other maps files)
I've used this RGN firmware file with firmware updater in pre-boot mode (I've tried with new created rgn file from a original GCD file without succes)

I can't use RMPrepUSB because device is only recogniced by Windows like Mass Storage a few seconds and it's imposible that the software format device unit.

Usualy I don't put map files on device memory, I put it on a MicroSD card (MicroSD card now is not in device)

This are my last steps:

1-Download original firmware file *.GCD
2-Use GarminCure3 with original firmware
3-Make Cure Firmware
4-Use updater to load Cure Firmware

Device reboots all time.

Detailed steps will be welcome

Thanks in advance

(excuses for my rudimentary english, I hope you understand me. If not, ask)