I destroyed my ZTE modem band with MDMA, please help me! [solved]

[sajunky]

I disagree. Now that ZTE modems are responding to +ZBANDI > 4 we should be looking enabling band setting for ZTE modems again (with a warning for old modems / firmwares about UMTS 900).

I wouldn't rush with this. Not that I don't believe alex_1992 that it worked on this particular modem. There are many older modems which would be screwed-up unintentionally and people frequently ignore warnings and press OK button in quick succession.

 

[ginggs]

I wouldn't rush with this.

I'll leave ZTE bands as they are for now (only enabled after command line switch), but add options for +ZBANDI=4 through 9.

Not that I don't believe alex_1992 that it worked on this particular modem.

Search for '+ZBANDI=8', there are a couple of hits (mostly in Finland and Poland).

There are many older modems which would be screwed-up unintentionally and people frequently ignore warnings and press OK button in quick succession.

Probably not that many. My guess is only first batch of UMTS 900 modems from three years ago. References to +ZBANDI=8 date back to 2013.

 

[sajunky]

I'll leave ZTE bands as they are for now (only enabled after command line switch), but add options for +ZBANDI=4 through 9.
[...]
Search for '+ZBANDI=8', there are a couple of hits (mostly in Finland and Poland).

Command-line option is a logical solution. I didn't complain earlier and now I feel more comfortable with.

And yes, I did my research. Even found some new commands:

3G-only and lock UMTS band to 900MHz only: at+zbandi=8 
3G-only and lock UMTS band to 2100MHz only: at+zbandi=6

And for LTE/4G devices:

LTE-only and lock LTE band to 800MHz only: at+zlockband=20 
LTE-only and lock LTE band to 1800MHz only: at+zlockband=3 
LTE-only and lock LTE band to 2600MHz only: at+zlockband=7

If you wish to include these commands, let me know I can search for (possible) side effects.

 

[ginggs]

3G-only and lock UMTS band to 900MHz only: at+zbandi=8 
3G-only and lock UMTS band to 2100MHz only: at+zbandi=6

I'm not sure I believe that "3G-only" stuff.
In ZTE modems this is normally done with AT+ZSNT=1

 

[sajunky]

I'm not sure I believe that "3G-only" stuff.
In ZTE modems this is normally done with AT+ZSNT=1

And value 0 gives auto?
I read that proper command for auto network selection is 'at+zsnt=0,0,0'

Forgotten: Return to LTE automatic band selection is 'at+zclockband=0'.

As I said, the side effects should be considered.

Edit: You are right in case of MF669, it doesn't force 3G-only. But there is a big mess here.