Soo. Thanks to a forum member (MANY thanks..) I know what's up - it's a faulty display board. As soon as one connects it to the phone, it reboots itself indefinitely. Luckily I have two spares so we'll have it replaced (he's very short on time and I've waited for ages, soo.. what the hell) and all *should* be fine.
Not exactly happy about FxTec's support though; they just stopped talking to me at all. I know I'm no longer covered by warranty but I am pretty sure they should've asked me to send the device back to them and find the source of trouble themselves.
But heck. I sincerely hope there won't be much more problems after this 😄
Well, I am out in the wild with my Pro1x. T-Mobile seems to have gotten better here. I seem to still be using band 4. Call was fine. Using internet on data now, no wifi. It's slow but steady. Even downloaded Firefox. As I said, slow but steady... no balking and quiting. I am wondering if US problems on T-Mobile have to do with which bands T-Mobile is relying on where.
Or if there are defective units, as @EskeRahnraised, is it many or just a few? Any are too mmany for those that have them, I understand, but if weren't hanging out at this forum, I wouldn't see any reason for testing.
Found my report from a month ago:
To repeat: I think I have seen the Pro1-X switch between LTE bands 3 and 1 without dropping dead. Band 20 seems to be the problem for me.
Unfortunately doesn't help. As (I think) I wrote previously, band 20 does not work, even if I enable the modem (or boot the Pro1-X) in that "zone" of my apartment. It will then directly go to the "no service" state.