Umi Plus - GPS Fix? Do we have alternative solutions?

Bash

Hello guys!

First of all, forgive me for my bad english.

Well, I guess that at this point we all know that Umi Plus have big issues with GPS, but I couldn't do anything to get this working. Here is my saga:

1) I bought a Umi Plus two months ago, it came with Android 6 and I had to enter in engineering mode and manually reset GPS positioning. Works well until I have the bad idea to upgrade OS to 7

2) Using OTA I upgraded my phone to Android 7 - Umi rom and everything goes wrong: many apps crashing, GPS totally broke, huge battery consuming, not charging with 'super charge' feature and some other minor problems. I had to fix this somehow, so...

3) I tried to manually downgrade my mobile to Android 6 again hoping that this would fix my many problems and the most important, get GPS working again. Doesn't work at all, when I downgrade using the official ROM + SFlash Tool my Umi Plus bricks with nothing more that a black screen without booting to OS. I literally tried all SFlash Tool options without success, as result I lost all my data (calculated risk).

4) My alternative was getting the official Android 7 rom and upgrade manually with SFlash Tool, Umi started to boot again and worked with your primal features such as fast charge and low battery consuming. I got some hope due these problems were fixed, for my 'surprise' GPS still very broke with the symtoms: suddenly I lost GPS signal, applications that uses GPS for tracking or route mapping such as Uber are unusable.

Can I somehow manage to fix GPS problem? This is really important to me and I saw no clues in other topics but a need of changing the entire mother board. Is that true? Can someone point me to a direction?

For those who doesn't believe that the GPS problem is not an isolated problem, two coworkers of mine bought the same phone and we all have literally the same problems.

Cheers,

Victor.

overrid3

Same issues here.
Compass going crazy too. Showing N towards E, then without moving the phone starts going round and round.
I wish I had one of the moderators' phone. They seem to work perfectly. (Having a feeling that only their phones work well)