Problems with Drive 50 and Maps

[japseye]

Got hold of a friends Smartdrive 50 who asked me to put on Eastern maps for him. Managed to live update Western maps to NTU 2019.02 which I do believe is installed on .system but no matter what I try I am unable to install any other map. I have City Navigator Europe NTU 2018.20 Original MapSource which I installed and unlocked then exported selected eastern maps using both Mapsource and customize Mapinstall. I tried putting the gmapsupp.img on internal and external sd card and .system and although Garmin Basecamp sees and recognized the file the unit will just not accept it. It just says Cannot authenticate maps, corrupt. Ive also tried downloading a pre unlocked image but this too gives same results.
When checking these files using Protected Garmin file toolkit_2254_x64.exe they are reported as valid and unlocked.
Can anyone please clarify whats going on. Ive spent hours on this.
Thanks

EDIT: Stop press. I found the solution by downgrading firmware. Been a while since I had anything to do with Garmin stuff

[debeliamark]

If you need to use latest maps with latest SW of unit then need to patch firmware inside of it to accept unlocked maps ... make a search about