can I replace the contents of the internal card with an external card with image written in it? So not having to disassemble the equipment. In that case what steps should I follow? Thanks
Yes. But sometimes users still need to disassemble unit and write backup image directly into internal sd card.
To restore your device without dismounting:
1) write backup image (using win32diskimager, dd command in *nix or something like this) into usb/sd flash of corresponding size.
2) use testmode_n.key type "copy device" written to FAT32-formatted USB stick (without additional partitions) to enter EasyRecovery mode.
3) execute Copy Device mode.
To restore your device with dismounting and extracting internal sd card:
1) use testmode_n.key type "mode change". Just after mode change please power off your device and don't power it on until you remove sd card. This removes password lock from internal sd card. Once you powered on your device, sd card will be locked again.
2) insert internal sd card into your desktop/laptop/cardreader.
3) write backup image directly into internal sd card.
Please make sure that you do not simply copy *.img file into sd card. You need to use special software (win32diskimager, dd, or other) to write image.
You can download 5000NEX image here: https://builds.casual-dev.com/index.php?dir=random%2FAVIC%2F