[Q] Radio issues following ROM update

Hey, thanks for clicking my post. TL;DR Since updating from ARHD 40.3 to Viper One 6.2.0, my radio has been having major intermittent issues. I have a HTC One m7_ul unlocked outright from Optus here in Australia. It is as of right now running the latest firmware linked to by the Viper One/ARHD threads, the latest TWRP, is S-OFF and superCID, running Viper One 6.2.0.

Symptoms:
1) No signal most of the time.
2) Signal appears to return during periods of movement (e.g. driving).
3) Even at full signal, there is no mobile connection (no data, no text/calling).
4) Once every few hours, when it has signal, it will gain mobile connection for a short period of time, after which it will cut out again - repeat to 1).

Here's a short story about how this came to be:

For many many months now it has been running just fine on stock firmware, rooted with S-ON running ARHD 40.3 (since that version came out).

About a fortnight ago I started noticing issues with my contacts application. Something to do with 501 contact link suggestions and certain contacts having hundreds of Facebook profile entries. This would cause issues in the People app (people just wouldn't load) and the SMS app (message histories wouldn't load, including new texts).

After some troubleshooting attempts, I resolved to reinstall a ROM. I opted to install the latest Viper One (6.2.0) successfully. It resolved my issues. However, it introduced a new one. The next morning I woke up to 4 texts from my service provider informing me I'd missed calls. I had no notifications as such, so the calls never reached my phone. I put it down to tower signal flex in my area. I left and as I walked out the door I noticed I had no signal (no bars, x above the icon in statusbar). Driving around seemed to fix the issue though, it got back up to normal values quickly enough.

However, even though I had plenty of signal and mobile data was ostensibly turned on, I couldn't get internet. I tried sending a text to myself but it failed send. Calls out simply waited on signal and then timed out. Every single other function of the device is 100% AOK (wifi, bluetooth, nfc, etc). The entire ROM is fully functional, can't find any other issues with stability or otherwise.

I put up with it for the day and get home and start troubleshooting. Here's what I tried so far, in order:
1) Change from Viper One to latest ARHD (71.1). Installed with no issues. Booted phone, no dice - no signal.
2) Checked SIM by moving to old iPhone 4 - full signal, radios work. It's not a service issue.
3) Revert to last known working ROM - ARHD (40.3). Installed with no issues. Booted phone, no dice - no signal.
4) Research research research. Think it might be a problem with firmware perhaps. Tried revone, failed because I'm not on 4.2.
5) Flash MaximusHD (11.0.0) in order to make use of revone for S-OFF/superCID. Flashed latest firmware linked in Viper One/ARHD threads.
6) Reboot phone. Still no dice with latest firmware on MaximusHD (11.0.0).
7) Retry with latest ARHD. No dice.
8) Retry with latest Viper One. No dice.

In every single instance, all the ROMs are fully functional except for mobile signal - wifi, bluetooth, nfc, etc. radios function perfectly. No issues with ADB or fastboot during any step of these processes. All my device info shows what I expect to see. I've searched as much as I can, to no avail. I turn to first-time posting here as a last resort to maybe find out what the issue is.

I am slowly reaching the thought that the hardware itself might be the issue. I'd appreciate any insight into what could be causing this - be it software or hardware - as well as if there is any way to test or diagnose the radio physically. Even just a confirmation ("Yep, sounds like your radio's FUBAR"). In the meantime, I'll be using aforementioned iPhone 4 (ugh).

Thanks for reading.

digitalism said:

Have you attempted to flash a different radio baseband?
Look up the radio version used in ARHD 41. If you find it, search for the radio within the forums and flash it. You can still keep the most current version of your preferred ROM. Search the threads for how to flash a radio baseband, there are plenty of them.

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I found a forum for HTC One radios here, it's in the AT&T section but apparently work on all HTC Ones. I was unable to find out which radio ARHD 41 used, my understanding is that custom ROMs don't usually come with a radio baseband of their own and they don't appear to list any on their thread that I could see. I would inquire but I think there's an issue with new users posting in development sections. Do you think it's worth trying to look further into what radio was used, or should I start flashing radios from the aforementioned list? There's a couple that stand out as possible candidates (the earliest version, the newest version, etc) but I'm not sure I want to just start going crazy on that list until something works. Or do I?

edit: To clarify, and they say explicitly in the ARHD post FAQ, they do not include radio/hboot/firmware in their ROM. So I must assume that I was simply on the stock radio the device shipped with.

edit 2: Confirmed my current baseband matches one of the ones indicated as installed from firmware package. I'm not sure what it was before I updated to Viper One or even while I was using Viper One.

Flashed the earliest radio baseband available from the aforementioned thread. Put the SIM back in, signal achieved, able to send texts/make calls/USSD codes. I was unable to get it to transfer mobile data, however.

Can't believe I didn't think about radio baseband. Didn't even know that was a thing. I just thought it was part of the firmware package. There you go I guess. Thanks again for the tip.

digitalism said:

No problem, just remember that if you're having issues with certain partitions on the device, each partition is technically flashable if you are S-Off and SuperCID.

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I've tried just about every radio in that forum. They all seemed to have the same issue for me - at first it seems to have no signal, then it gets normal signal, receives/sends any buffered texts, and then fails to work after that for any purpose regardless of signal. I think I'm back at square one; I don't suppose there are any other simple things to try?

First, thanks again for your patience and assistance.

digitalism said:

Also, make sure you are installing firmware particular to your device. For instance, do not install firmware originally meant for an AT&T phone if you use Verizon or another carrier.

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I was not aware of this restriction. I suspect I may have flashed firmware for a different region. I isolated the Optus firmware RUU numbers and got a firmware package matching, and the android-info.txt matches the device original CID and modelnum. I'll try it soon.

I'm still having trouble understanding, though, how it could have failed in the first place. My phone was S-ON when the radio stopped working; surely changes to firmware/radio couldn't have occurred anyway? None of the ROMs I've touched have firmware or radio included as far as I could tell.

Flashed the firmware appropriate to my region (4.20.980.1). Came with radio. Rebooted, put in SIM, no signal for 5 minutes. When I get signal, texts don't send and calling times out, USSD codes give connection problem errors. Same as before. How likely is it the actual hardware could be damaged? I did drop it on concrete, on the front of the device at the top, around the time this started happening - very shortly before I flashed Viper One to fix the contacts issue. There was no visible damage.

digitalism said:

Quick question:

Are you installing your firmware and software without the SIM card in? If so, I would leave the SIM card in and have all the software installed during the process. Damage to the phone should not cause problems for connecting to the cellular network. Have you tried leaving the house, going outside, or getting into a different area to try your signal? Maybe your house is a deadzone and the phone is having a hard time picking it up. My room gets like this since I live in Florida where houses are built with cinder blocks to prevent hurricane damage. It really messes with my signal.

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Good ideas, but unfortunately not - every firmware and radio package I've flashed, I've done once with the SIM, once without, thinking along a similar line.

I'm in a known good cell location - coverage in my area is fantastic with my provider (Telstra, usually get 5 bar signal on 3G - I do not get LTE on my plan). I test in multiple places - next to my PC, outside the house, down the street, etc. The behaviour I've noticed is that I have no signal regardless of where I go, for about 5 minutes after booting the phone, after which it gets signal, sends/receives any buffered texts, and then fails to communicate successfully after that (i.e., I get the test text I sent myself, then I resend another test, and it fails to send). The iPhone 4 I've been moving my SIM to has been receiving full signal (as expected) at every place I've been testing the HTC One.

digitalism said:

Other than that, I honestly couldn't tell you what your issue is.

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Tried the APN thing. There was indeed a few things different from the listed settings, but honestly, they were pre-populated with a bunch of Telstra data beforehand when the SIM was in. I made the changes and noticed no difference.

Thanks again for your help. As a last step I will return it fully to stock. After that I suspect my only recourse would be taking it back to Optus and asking if they'll quote me to fix it.

SaHiLzZ said:

Unfortunately it does seem to be hardware issue from the history of what you have tried and posted.

Use nkk71's guide listed in my signature to go back to stock for warranty but substitute your local RUU/nandroid/etc.

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Thanks for the link, that's actually one HTC One return-to-stock guide I haven't seen yet and it looks very concise. Cheers.