It's not even getting as far as the commands it seems. White screen indicates it's trying but failing, then trying to boot again, trying to read from card .... ad infinitum. SD card commands are executed by Ldr.bin after fw is invoked, maybe there is a compatibility problem with V2.20's boot.bin/Ldr.bin and V1.16's fw contained in region 14.
Suggestions:
1. Erase the card and re-insert it to see if the device reacts any differently.
2. It it boots normally, try using boot.bin modified with first instance of "0C 80 A0 E1" changed to "0C 80 A0 E3", then made as RGN file flashed with Updater.exe to execute these commands:
rrgn,14,1:/Garmin/14-1.bin
reboot
(See kunix's [Only registered and activated users can see links. Click Here To Register...] for complete explanation).