You need to flash or boot custom recovery TWRP or CWM. That recovery is probably custom recovery, but there is no scatter. I don't think Doogee 550 has fastboot.
Do you have custom recovery on your phone already? If you do, then copy those files to your phone and boot into recovery and "restore" that Nandroid backup there.
If you don't, then get custom recovery on your phone and restore that Nandroid backup.
By the way, this is quite unlikely to be real 5.1. There was never any 5.1 kernel released for MT6592. Probably just a skinned and modded 4.4. I could be wrong, but that's my guess.
Getting TWRP recovery , Copying rom 5.1 file zip on sd card, starting with recovery mode make Wipe factory reset and cache data, when i try to install the 5.1 rom i received message "Failed" don't find MD5 file.
rom 5.1 installed successfully, all works fine except Radio and all contacts on the sim cards has been lost,( No contacts on your sim card) how can i do to import my contacts ?
(2016-01-25, 04:22)dave65 Wrote: rom 5.1 installed successfully, all works fine except Radio and all contacts on the sim cards has been lost,( No contacts on your sim card) how can i do to import my contacts ?
Ah. Sorry did not reply to your earlier problem. How did you fix the situation?
For the contacts, did you try the import function in the dialer?