[ONE Q&A, Help & Troubleshooting] johnng1986:
I want to start by saying thank you to everyone on this forum. I have learned so much from reading the guides and resources (particularly those by [MENTION=6363737]Gawd[/MENTION], [MENTION=1032410]spanna[/MENTION], [MENTION=4153349]Heisenberg[/MENTION], [MENTION=2258271]EddyOS[/MENTION], and [MENTION=4841620]Timmmmaaahh[/MENTION]. I know some may have moved on but you legacy remains.).

This issue seems to have come up before on the forum, but I have not found one that matches my own situation with a solution, unless I am missing something. I am also lucky in that I have access to another near identical OPO without the issue for comparison. I am visiting my family and we all have OPO.

I have noticed that my phone will have decent to good signal (1-4 bars of Tomobile LTE) be able to use cellular data and send SMS, but not make and receive phone calls in certain areas. I would have been content saying this was a reception/carrier issue. However, I am visiting family for Memorial day and have been able to troubleshoot this with their phones. I bought my parents OPOs when it came out and my brother has a Find7, so we all have essentially the same hardware. For my troubleshooting I used primarily my mother's OPO (not updated since CM11S:eek:) and occasionally my brother's Find7. Both my mother and I have the 64 GB edition of OPO purchased around Oct-Nov 2014. Both are cobranded with Cyanogen, though mine was purchased a month or two prior to hers. When comparing the OPOs I notice her phone is able to send and receive calls in places where mine is not able. We have similar reception. I have cellular data and can still SMS. The issue is just with calls. I have tried the following (i have bolded things which I noted were different):

Basic stuff:

1) Making and receiving calls with both phones side by side. Her phone can send and receive calls in all areas (even with just one bar), while mine can only make and receive calls in some areas. My brothers Find7 has identical performance as my mothers phone.

2)Toggling airplane mode. -- Same result.

3)Toggling LTEonly, 3g only, and 2g only. -- Same result.

4)Verifying APN -- Identical for all three phones

5)Swapping SIM Cards -- both phones perform the same irrespective of which sim card is in it.

6)Verfied IMEI -- present in all phones.

7)Verifying signal strength (dBm/asu) in phone settings (*#*#INFO#*#*) -- near identical between phones. Our dBm numbers were the same but my asu number was sometimes triple her phone's asu. Her's was identical to the Find7.

More advanced stuff:

8) Removing the back cover and making sure the terminal are making contact to the backplate antennae.

9) Changing roms and firmware. No success.

- I had recently upgraded from the final release COS 13 to the latest Oreo RR with a clean wipe using TWRP. I was running RR when I first started this.

- First I tried flashing my recovery file with TWRP. It says it ran successfully, but didn't make any changes to the system.

- Since my mothers phone has no issues I tried to replicate her setup. I fastboot flashed the cm-11.0-XNPH05Q-bacon-signed-fastboot.zip provided by spannaa.

- I found some similar posts to my problem which linked to gawds firmware. I verified that both my mother's working OPO and mine had the same OS (XNPH05Q) and baseband (c7-00020) I also tried flashing different firmwares with no benefit.

- I tried fastboot flashing back to COS 11 XNPH33R (what my OPO came out out of the box with).

- I then used EddyOS guide to return device to stock COS 13.1.2. with no change.

- Thinking another new ROM may include a better firmware. I most recently did a clean install of AOSPExtedned and currently have baseband c6-0241.

Going forward:

- I was thinking of flashing gawds firmwares with AOSPExtedned. Is this safe?

- Looking to disable/unlink my google voice account from my cell number. My mom does not have this set-up. I noticed a delay in making calls, and that my google voice account has a log of all my missed calls (those that never make it to my cell). Maybe it interfering with my calls going in and out.

- Any suggestions on diagnostics I can run while I have access to my Mom's functioning OPO.

Much thanks for everyone's help.