If you change string in boot.bin from kunix solution nuvi can read from SD card from update.txt
If you flash with 2.bin nuvi change ID when you read with tool go7win becouse read xml from folder Garmin where is diferent ID of nuvi.
So this mean that flash is posible but some other region prevent to turn on nuvi,we must find what region is show this software missing.
Maybe is region 91 i dont know i will try all posible solution.
If is region changed with update.txt after restarting nuvi is all the same like before flashing.
What will be if i erase region 5?