While performing a map update via the GarminMapUpdater software, the unit became unusable. So I proceeded to

Reflash the Nuvi 54LM in pre-boot mode (Garmin usb drivers installed) using GarminCure3 v0.1 to load the Cure with file: nuvix2andx4_GCDFile__400.gcd

Note: I could not find any explicit reference to Nuvi 54LM software version on this site so I used:
[Only registered and activated users can see links. ]

Was able to flash the device using Updater.exe

However on reboot, it shutdowns in about 2 secs and am unable to format it in RMPrepUSB within this time. It appears in RMPrepUSB momentarily but before I can go through with the formatting sequence, it shuts down

Am able to reflash it using Updater.exe tool again but same shutdown in ~2 secs symptoms exist.

1. Did I use the right nuvix2andx4_GCDFile__400.gcd file for the Nuvi 54LM device? Is the shutdown because I used the wrong software update file?

2. Any magic sequence to make it not shutdown in 2 secs so that I can format it using RMPrepUSB?

Thanks in advance!