Thread: recovering Nuvi 40 from failed firmware upgrade without USB

I have a Nuvi 40 with a failed and un-repairable USB port.

Thinking it would be simple to upgrade the firmware, I put the version 4.00 gupdate.gcd on the SD card under the Garmin folder and power-cycled it (a few times).

But something bad happened. Perhaps it was due to the failed USB port interfering with the upgrade or perhaps I reset at the wrong time. In any case, the software versions now read: GPS: 2.90, Text: 2.30, Keyboard: Unknown, and Audio: Missing. Although the device boots and runs, I've lost lots of functionality (all voice output, original maps, QWERTY keyboard, help, ...). The most pressing issue is that I have no voice output and without this the unit is not very useful. The details are [Only registered and activated users can see links. ]

I am still able to back up region 40 using Ldr.bin and update.txt so I'm somewhat hopeful that I can recover, but I'm not exactly sure how.

One idea is to use RNG_Tool to change the SW version of a GCD file to 4.01, put in in gupdate.gcd and see if that forces an upgrade. But I'm worried the same thing would happen if the problem was related to the non-functional USB port interfering with the upgrade process.

Another would be to use update.txt commands (xrgn?) to write fw_all.bin right into the appropriate region. But I'm not sure that simply copying fw_all.bin to a rgn is equivalent to an upgrade.

Any advice would be appreciated.