I have read this thread today and for me it sounds similar to No internet at all. There I described my problem and what I have done before.
Because you have written in this thread that you had changed /etc/permissions/platform.xml (i.e. /system/etc/permissions) before the problem appeared I remember that I have done the same to fix the Ext SD card permission issue.
Maybe some ways changing platform.xml are dangerous. If I remember rightly I have copied the file from PC to FP2-ExtSDCard and further copied the file with ghost commander (file manager) to /system/etc/permissions for which I had to remount /system with RW option. Probably I have forgotten to remount with R option after that and this was the failure.
For me its too late because I have reflashed my FP2 with Open OS 16.06 but I wanted to write down my experience for other users.
UPDATE: Today I have changed platform.xml as described in SD Card no writing permission in FP2 (mind the missing read permissions) and the phone is still running 
UPDATE 2: Sorry but this wasn’t a solution. Again my phone was unusable (no network). Recommending doing changes to platform.xml only in recovery mode. See SD Card no writing permission in FP2