When you enter in pre boot and updater see your device and you click OK button you must still hold uper left corner of screen ( don't release finger from screen )
I think you remove finger from screen and this is way you have error or you whait to long and nuvi close pre boot.

When updater.exe see your device you have only 10 sec to click button OK if you don't click it on 10 sec your nuvi go out of preboot.