Very strange. My old MiA1 (now bricked) lost LTE band 20 somewhere back in april while testing various custom roms. Never got the band back even with the help of low level qualcomm tools. I too live in germany but I'm on o2 and in my rural hometown there is only moderate lte b20 - nothing else not even 2g
By the way: Try dialing *#*#4636#*#* select Phone Information and fro the top right menu "Select Radio Band". Try "Band 800 DD" or somthing similar if listed if you're in lte b20 range. You can checkout where your carrier offeres b20 with this slick tool:
https://www.cellmapper.net/map
Anyway happy new year :highfive:
Thanks, mate. I am considering using LTE (I'm on Lidl Connect in the vodafone network) - but since there is only EDGE around where I live I don't know if that would help...
However, I don't need the phone during the holidays and was able to back everything up and make some tests. I actually went back through ALL and EVERY modem from Joeyhuab's thread, even restored my LowLevelBackup and found my Band 20!
But guess what: I found it on the November Stock ROM from 2017!!! :laugh: Android 7.1.2... well. Since I went back to stock I am now upgrading through some tissot images and keeping an eye on the basebands. I'll try and get to december without losing it. I'll report back.
EDIT: Soo, this might not work for you, but here's what I did to get Band20 back.
1.) Revert to previous EFS/modem. I had a LowLevel backup from treblizing.
2.) Using the bash scripts (flash_all.sh) I flashed the official tissot images 7.11.18. This is the same process than MiFlash does. I personally went down 8.1.10 and from there to 7.11.18 but I do not know if that is needed.
3.) On stock 7.11.18 I had the correct bands selectable and updated directly to "tissot_images_V9.6.8.0.ODHMIFE_8.0"
4.) From there I did not get the Pie stable update so I hot-booted the "boot-recovery.img" from the PixelExperience thread and installed the TWRP-Stock-Pie-stable zip from this forum.
5.) Now I had Band20 on Pie with december firmware.
6.) last step: Format data, install Lineage (btw: 20181229 zip is not linked in Post #1) and Band 20 is still present. I won't touch my firmware again until absolutely necessary.
And guys: make backups.