Drop on back bootloop, repair shop fail

I'm currently travelling, and whilst in Cuba I proceed to drop my phone flat on its back which causes it to bootloop. This happened to me in Canada as well, where I opened it up reseated the display cables and was good to go, when I tried this in Cuba, it did not solve the problem. It was and is still in a bootloop on the apple logo and then black.

From research on this site I assumed it was an issue with the battery, so I have taken it to a repair shop where they reseated it and tried a new one, but it failed to fix the issue. It is still in a bootloop.

They gave a load of excuses and no real reason to why it is broken other than my jailbreak my have been the cause, which I find very hard to believe. They then suggest that I try a restore, which I have just attempted to which I get error (9). Which I think means a hardware issue.

If the battery is not the issue, the only hardware problem I can think of is from screwing the wrong screws on the guard of the display cables, would this be the cause? How do I go about checking this and fixing it?

iPhone 5s 10.2

Jailbroken Yalu b7