I apologize in advance for such a lengthy post - I have attempted to provide every relevant detail, as I have exhausted all the solutions I could find on the forums.

Some time after updating my maps about a year ago, I've started to experience frequent reboots on start-up. Typically, my 2460 would restart 4-5 times before stabilizing.
In an effort to alleviate the issue, I've decided to update the unit. Garmin Express updated my firmware to 3.60 (from 2.80, I believe), and my maps to the latest North American map set, along with a few other modules (Traffic providers, etc.). There was a warning regarding insufficient storage on the device (I do not have an SD card installed), but I was given the option to install a subset of the maps. The upgrade appeared to have completed successfully, but I do have my suspicions that some corruption might have occurred due to storage constraints.
My Nuvi is now stuck in a permanent reboot loop. It will reboot within seconds of turning on, upon displaying "Loading Maps" or the PIN screen. This is occurring whether or not the GPS is plugged into a PC.

Things I have tried:
Resetting user data - I have performed this via the long-press on the lower-right corner trick.
Kunix's GarminCure3 - This works like a charm (I must've performed it a few dozen times at this point), and I'm able to access the Mass Storage on the device. I have initially deleted the GCUPDATE.GCD, with no luck. I have since attempted to delete/replace various other (potentially corrupt) files.
RMprepUSB - Eventually, I have formatted the drive with RMprepUSB. At this point, I have reflashed with my old 2.80 firmware, and the GPS actually connected to the PC successfully. I've run Garmin Express, which updated my firmware to 3.60 and instructed me to reboot. Restarting the GPS has again put it into a reboot loop.
I have since tried various combinations of firmwares/files with no success. Whether the GPS is completely empty or has the .system directory populated with files such as gmapprom.gma, gmapbmap.img, Locales.xml, etc. seems to make no difference.

The GarminDevice.xml does not get fully generated. I have a GarminDevice.tmp file in the Garmin directory. This file is slightly smaller than a fully formed GarminDevice.xml (26K vs 32K). The \.System\Diag\Shutdowns directory is full of "Data_Abort" files, which I'm unable to interpret. I find it odd that GarminDevice.tmp contains numerous references to specific Voice files, etc. which are no longer on the file system. Is this information coming directly from the firmware?

I am suspecting NV memory corruption. Is there a way to reset the NV memory in a non-bootable system?
Should the 2460 be able to boot with an empty file system? If not, which files should I put back onto the GPS? Between my backups, Garmin Express downloads, and files I've snagged off Noeman.org, I believe I have a fairly complete set of 2460 files.
Perhaps the battery status has something to do with the reboot. Unfortunately, I'm unable to check the battery levels. Moreover, the unit keeps rebooting as it's plugged into either a USB charger or its cigarette-lighter dashboard mount. Thus, I can't tell if it's actually charging.

I would be happy to donate to anyone savvy enough to bring my GPS back to life.
Thank you for your time!