Zenfone 2 ZE550ML camera KO after screen replacement

A few days ago I have ordered and then replaced the LCD of my Zenfone 2. Sending it back to repair the display was as expensive as buying a new phone, so I decided to take the risk. I followed the instructions I found on the internet and I succeded. Both touch and display work after replacement, and all other components work too, except for camera functions. Now when I open any camera app (Google Camera, Zenfone Pixelmaster camera and so on) I get the infamous "camera failed to launch, please reboot your device". After cleaning up both application cache and system cache (I have even tried flashing an older firmware version) I decided to check both the flat cables connecting the front camera and rear camera to the phone's motherboard, with no success.
Any clue about how to proceed ?
Any chance that trying a different ROM (such as Cyanogen) might fix my problem ?
I have read that many users are experiencing that nefarious camera message, however I haven't found any effective solution so far, and without a clue I can't figure out if one of the two cameras is broken or damaged...
Suggestions ?

Thanks in advance and have a nice day
Azrahel