I just received an AZ GTi mount from FLO and immediately got myself into the same situation. After turning on the mount for the first time, I connected my PC to the SynScan wifi without issues. At this point I had already tried connecting with the Android SynScan Pro app, but it continually refused to connect ("no device found") despite connecting to the wifi hotspot fine. I hoped a firmware update would resolve this, so I downloaded the MC firmware loader v1.79 and AZ GTi motor controller firmware "right arm" v3.39.
Same story as the others here - tried to flash firmware, update failed, I cycled the power as instructed. But it just kept failing around 10% in. I moved the mount as close as physically possible to my PC and retried, but no luck. The mount's LED was flashing three times on a loop. Thanks to this thread I realised that indicated it was stuck in the update mode. I was not able to find an older or alternate version of the firmware on the SW site. At this point I had the sinking feeling I would have to return the mount.
The fix in my case was simple but quite frustrating - I repeatedly tried the firmware update over and over again until it finally managed to complete. Usually it would not get more than a few percent in, but after it got to 46% on one attempt without failing, I was spurred on. After I would guess 50 attempts it finally completed and I rebooted the mount. The android app connected first time without any issues (connect settings are network, 5 resend tries, 500 ms timeout, find devices on, and IP set to 192.168.4.1, although I don't think that setting is used in find devices mode). I can now slew the mount using the android app which still seems to be connected after the time it took me to write this post, so it's looking good!
I know Skywatcher has a bit of a bad reputation for substandard software, but you would think after people experiencing this same issue for 4 years, they would have been able to fix the firmware loader by now, or at the least give the user some more control over timeouts etc.
Thought I would post this here in case anyone else is in the same boat! Persevere!