WARNING: Never Change Radio Band

[TomKay]

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 

1. without an explicit alternative being offered (implying the one choice must be OK), and
2. without being asked for confirmation (for such a significant change), and
3. 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.

[TomKay]

Just to repeat that there is a solution, i.e., a way to recover from selecting the wrong radio band.

One has to create a backup of the phone, factory reset it, and then restore the backup.

Obviously the factory reset on its own works as well, but most would probably want the "fix" to have the least possible impact, hence the recommendation to make a backup first.

Note that a backup does not cover everything, so for instance you may want to record how you placed your app icons, or other configuration details that may not will be restored.

[9elsen]

Well I admit I did it. And used 4 hours before I found this description. Thanks TomKay.
To Feel. By 'android user' do you mean rooted on th phone?
My phone is not rooted so I guess I have to take the long road.
My reason for being in the interesting menus was That I find that my phone does not function as well with 🍭 on.
Is there any new fix for this btw?

[9elsen]

Sorry not Feel but Feek

[Tasfique]

The easiest solution is flashing the baseband with flashtool... worked for me, no data were effected

[maxiimum]

Thank you for mentioning this problem
I'm from Tunisia and yesterday I had the same problem, I pressed the button accidently and you can't change it after that 

Now, in the current time, I'm going to copy the files from the internal memory then restore the phone (factory reset). 
I hope I will a signal back ...

[Akash_tkr]

It works I was also suffering from that issue...
i did same procedures and signal came back but lost my SIM which was in slot one....
SIM in slot 1 got blocked....
Sim got blocked only on my mobile  phone...
but was operating well in other mobile phones...
bought duplicate SIM and then now its working good.....

[oalgvi17]

hi friends,

I have the same problem.

I have installed MTK Engineering Mode but not working with my phone.

unfortunatelly, my phone is not a MTK android.

it is XIAOMI MI5 dual sim, but not rooted.

a very new phone on which both slots work LTE/4G/3G simultaneously.

(no other dual sim works in the same way.

all other dual sims work LTE/4G/3G on a slot, and 2G only on the another slot.)

I did factory reset 10 times, but not working.

any idea, please?

do you know what to erase to not restart again with USA BAND after factory reset?

will I flash it?

thank you.

[cmantas]

Hey, oalgvi17, if you only have one sim, try putting it in the other slot.
It worked for me until unfortunatelly (or more like stupidly) I repeated the mistake for the second sim too.
Anyone have an idea on how to revert it?
I cannot even get an sms for unlocking the bootloader so as to try flashing anything

[oalgvi17]

unfortunatelly I have damaged both slots.

any other ideas, please?

[cmantas]

Yes, I finally fixed  it with this:

http://www.honorbuy.com/forum/thread-360053-1-1.html

same process is explained here (try using google translate), and also here, however I think the first one is more concise.

Also you might need some qualcom drivers (QDLoader HS-USB Driver). I have uploaded in my google drive here, but you could also google it.

Be adviced:

a) you could brick your device - I nearly did mine.

b) it took me a whole morning, so relax and be prepaired to spend some time.

c) At some point, halfway through the process I got an error, something like “Not enough storage is available to process this command”. At this point I was essentially left with a brick.

However I installed everything in another PC, restarted the phone in fastboot, etc and did it again and (after a couple of tries), it woorked.

The link from the 'honorbuy' site is also for the global ROM, which is good.

Good luck!