[E 2015 Q&A, Help & Troubleshooting] :
I apologise for not explaining this fully, meaning you made a completely unnecessary and incorrect reply (only because I gave you incomplete information)

So let me explain fully.

My moto e had issues around the 05/04 build of CM13.

After an upgrade from 04/04 to 05/04 via "dirty" flash (only wiping dalvik and cache) the moto e "hung" and got stuck on the "splash" screen and would not boot.

Returning to twrp to wipe system/data/internal storage was futile, it still would not boot past the Motorola boot logo.

Several people suggested I return my moto e to stock, so I duly returned it to stock BY FLASHING THE EU RETAIL 5.0.2 FIRMWARE FOR XT1524-(the variant of moto e I have)

This was completely unsuccessful as although I returned to stock, I left the bootloader unlocked and re rooted and reflashed twrp as soon as I had successfully returned the device to stock.

After booting into 5.0.2 I checked everything was fully working but found the device to be very slow, extremely laggy and stuttery.

Further research suggested UK users who had manually flashed the 5.1.1 update (you must remember UK has NEVER been offered the 5.1.1 update, as Motorola announced in December 2015 UK was skipping 5.1.1 to go straight to 6.0) got the OTA update after successfully flashing said 5.1.1 EU firmware.

This was again unsuccessful, with the device not quite as slow and laggy as 5.0.2 but now was running a firmware it should NOT have ever received.

Concerned this was my issue and sceptical of the advice I had received about the 5.1.1 firmware, I flashed the EU retail 6.0 stock ROM

I found it

Slow

Battery intensive

Laggy and stuttery, there was no fluidity, the screen movements were at best "jerky"

Ringtone volume reduced to the point I missed incoming calls.

Random reboots.

One point I must make to you and anyone else reading this is to

NEVER FLASH FIRMWARE FOR ANOTHER DEVICE OR FLASH INCOMPATIBLE/FIRMWARE NOT DESIGNED FOR YOUR DEVICE.

That is a very big no no and should not be attempted for any reason.

For example, if I flashed firmware for an XT1521 on my XT1524, I would permanently brick my device.

Same if I flashed XT1527 or XT1523 firmware.

No one should be attempting to flash incompatible firmware.

And to someone who messaged me asking if he could flash a "no carrier" firmware from an XT1526 on to an XT1524 to make this a no carrier unlocked device is simply "NO!"

Flashing a no carrier firmware on a carrier locked device will brick it.

Flashing XT1526 firmware on an XT1524 will brick it.

There may not seem much difference between these variants of devices but I'm told they are quite different, that's why they are numbered in such a way to make them different to the continents for which they are designed for.

This is not my opinion, this is fact, openly found here on XDA and read many times after people have knowingly flashed the wrong firmware on the wrong device and suffered a permanent brick!

I'm pretty sure most of my problems came from flashing 5.0.2 and 5.1.1, and since I had upgraded to 6.0.1 running CM13, I simply made the problem worse but not downgrading modem/bootloader.

I hope this explains my situation fully, but I've found the last security update to CM12.1 (17/04) the most stable custom ROM available for Surnia although I am now back and happy finally with CM13.

Regards.