[Q] HTC One M8 Verizon - Radio band missing after messing with phone info settings topic

Hi Guys.

Short info:
- before: HTC One M8 Verizon, Android 4.4.4 (RUU M8_VZW 4.4.4), rooted, S-OFF, Super CID, TWRP 2.8.3.0
- after: HTC One M8 Verizon, Android 4.4.4 (Viper OneM8 3.2.1), rooted, S-OFF, Super CID, TWRP 2.8.3.0.

Few hours ago I finished "converting" HTC One M8 Verizon from 4.4.4 to T-Mobile version, successfully installing Viper OneM8 3.2.1 over 4.4.4 RUU firmware, as described in this post:

http://forum.xda-developers.com/show....php?t=2710720

The main reason for the above was lack of LTE services under Verizon firmware (I live in Europe).

Finished installing Viper ROM, configuring phone, restored content (apps, contacts, settings etc) - part of it manually. LTE still not available, and continued to verify.

In the end I started to check Viper Tweaks section, and finally got to Misc - Phone info. While there, I checked also Radio bands, and I was stuck in the radio menu, with only 3 options (US Radios, 900-, 1900-). Had to select one to continue, and ... the winner was 900-. Instantly lost GSM signal and never came back.

Just to be nicer, after reboot (normal reboot), 900- option disappeared from Radio bands in Phone info advanced menu, and never came back. No matter what I did.

What I did try (all with full wipe / formatting etc):
- resetting Viper ROM
- reinstalled Viper ROM
- reverting to RUU M8_VZW 4.4.4 nandroid backup (saved before first installing Viper ROM).
- reverting to clean RUU M8_VZW 4.4.4 firmware
- flashed 4.4.4 radio from this topic: forum.xda-developers.com/verizon-htc-one-m8/development/radios-0-89-20-0222-t2824882
- reverting to Viper One ROM, this time installed with T-Mobile version. Same outcome, different message: "error er05 invalid sim".

Error messages stepped on:

Constant: "The SIM card is from an unknown source"

From time to time: "your SIM card does not allow a connection to this network."

If I tried to select GSM network and search for operators (manually / automatic): "No network found. Select "Yes" to switch to global mode, or Select "No" to stay in current mode." And "Error searching for networks" / "No networks found".

The only thing that did not have possibility to check (yet): SIM card health.

UPDATE: SIM card checked and OK, phone registered finally (T Mobile version of Viper One had also "Auto" option under Radio band, in Phone info hidden menu! :eek:).

Still working on this, managed to solve it while compiling this post, but still have the question: what have I done so wrong, and how can I get back to the "good" setting? Is the radio band setting so resilient to full format, several ROM's and resets, even radio firmware change?!

I will revert with updates!

Thanks!