[One (M8) Q&A, Help & Troubleshooting] oRAirwolf:
I cannot get my cellular connection to stay up for more than 5 minutes after flashing Sinless 4.0.1 or Sinless 4.1.0. The trouble started when I flashed the M8-L firmware that was linked in the Sinless ROM thread. At the time, I was running the T-Mobile 3.32.531.2 firmware with Sinless 4.0.1 with no problems. After flashing the M8-L firmware, the phone will connect and get LTE, but then go to No Service after about 5 minutes and never recover.

After trying to flash a bunch of different firmwares and radios to fix the problem, I went with the nuclear option: I re-locked the bootloader and used an official HTC T-Mobile RUU and restored the phone to 1.57.531.7 (using this guide). I then went to the HTC site and upgraded using the HTC T-Mobile RUU to 2.22.531.5 (this one). From there, I unlocked the bootloader again and flashed Philz Touch Recovery version 6.57.8 . I used the "Clean to Install a New ROM" wipe option in Philz, which formats the Data, Cache, Datdata, SD-Ext, Android_secure, System, and Preload partitions. I then flashed Sinless 4.0.1 from Philz. The phone booted up, but I ran into a problem I previously had where WiFi was not working, but I was getting a cellular connection. To fix this, I did what I originally did and flashed the T-Mobile 3.32.531.2 firmware (from here and here) and then used the same "Clean to Install a New ROM" wipe option and re-flashed Sinless 4.0.1. After the phone booted, the WiFi started working again, but I ran into the same problem where the cellular connection died after about 5 minutes and it said No Service.

I am able to get the phone working if I restore from a Nandroid back to Sinless 3.6.0, but as soon as I flash 4.0.1 or 4.1.0, I run into the loss of cellular service issue.

I am at a complete loss at this point. Can anybody suggest a fix? Again, everything was working fine, including Sinless 4.0.1, until I flashed that M8-L firmware.

Here is my phone info when running the Nandroid backup of Sinless 3.6.0:

C:\Program Files (x86)\Minimal ADB and Fastboot>fastboot getvar all
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: 1.22.21331147A1.29G
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 3.28.401.9
(bootloader) version-misc: PVT SHIP S-OFF
(bootloader) serialno: FAXXXXXXXXXXX
(bootloader) imei: XXXXXXXXXXXXXX
(bootloader) imei2: Not Support
(bootloader) meid: 00000000000000
(bootloader) product: m8_ul
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B13000
(bootloader) cidnum: 11111111
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: off
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: df77f8b7
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
all: Done!
finished. total time: 0.018s

Here is my phone info when running Sinless 4.1.0 after a full wipe and flash over the Nandroid backup of Sinless 3.6.0:

C:\Program Files (x86)\Minimal ADB and Fastboot>fastboot getvar all
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: 1.22.21331147A1.29G
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 3.28.401.9
(bootloader) version-misc: PVT SHIP S-OFF
(bootloader) serialno: FAXXXXXXXXXXXXX
(bootloader) imei: XXXXXXXXXXXXXXXX
(bootloader) imei2: Not Support
(bootloader) meid: 00000000000000
(bootloader) product: m8_ul
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B13000
(bootloader) cidnum: 11111111
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: off
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: df77f8b7
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
all: Done!
finished. total time: 0.113s