Perhaps this warning will save some users a lot of painful hours.
I just spend hours on end to get my phone back to normal because I had accidentally changed the radio band to "USA band" and there is no easy way to revert that.
Now one could argue I should not have accessed the testing menu in the first place, but the phone was getting a bit warm at the back and I wanted to check the temperature. I had forgotten where to look exactly so I looked around a bit and once I saw "radio band" I was curious which options would appear.
After selecting "radio band" only one choice popped up "USA band". Now had I not been still a bit stressed from a phone call and been a bit too tired, I might have figured out that I should have pressed anywhere outside the button, but, PLEASE, if there is only one option, how can it be a wrong one way street?
I had to backup the phone, factory reset it, restore the data and recreate all my settings and app icon arrangements. I couldn't choose the firmware I had been happy with but had to jump to 157 (with unknown consequences). I had issues with some applications which updated to newer versions without my approval so some saved game states won't load back anymore. Luckily, I could revert to an older version of Chrome which does not ignore bookmarks placed on the homescreen (why do bugs like that not get fixed? But I digress). I had to find a workaround for my phone being unable to pair with my PC anymore and luckily I found an answer on this forum.
Fortunately, I anticipated that my app icons won't reappear at their previous positions despite the fact that I tried the phone back up and a PC companion backup, and had taken pictures of my home screens before the factory reset.
I literally spent six hours just because my finger was a split second quicker than my brain when I was faced with a "one option"-choice while searching for the temperature reading.
I appreciate that a testing or a service menu must be approached with caution, but even experienced technicians make mistakes from time to time. AFAIC, there should be no way (I'm sparing you the expletives here) to essentially render your phone useless with one touch of a button
- without an explicit alternative being offered (implying the one choice must be OK), and
- without being asked for confirmation (for such a significant change), and
- without an option to go back and reconfigure the correct band (why make it a one way street?).
It leaves me puzzled how anyone could set up a combination of all these three factors, be it in a service menu or not.
