[T-Mobile Samsung Galaxy S 5] gotissues68:
HI All -

I've posted in the Help/QA forum and didn't get any responses so I thought I might be able to reach a wider audience in this forum. I have the G900T and NFC is only half working and I believe I somehow manage to break it, but now I'm trying to see if there is any way to fix it. The issue is that Tap and Pay works, but Android Beam and any app that reads anything that emits NFC signals such as NFC tags, my yubikey-neo and an app which can read passports no longer work.

I initially noticed the issue on my phone and thought it was hardware related and was granted a warranty replacement by T-Mobile. Once I received the replacement phone I went through my usual setup.

1. Rooted via the NE6 boot image and towelroot method to gain root and then flashed the NK2 boot image back.

NFC worked as expected after rooting.

2. I used PC Odin and flashed twrp which tripped knox which I didn't care about since I don't use it, although clearly it voids the samsung warranty.

NFC continued to function correctly.

3. I backed up my rooted installation and decided to flash the latest CM12 KLTE nightly and play around for a few minutes. I then restored my original rooted TW install.

This is the point where NFC began to no longer function as expected. As mentioned Tap and Pay works fine, but I can't read anything emitting NFC signals. I also can't use Android Beam or S-Beam.

I have tried the following :

I used PC Odin to flash the original stock NK2 image and the issue persisted.

Afer backing up the /efs partition just in case it was somehow related ( no clear reason led me to believe it was ) I used PC Odin option to clear EFS and also used NAND Erase and flashed the stock firmware again and performed a factory reset. The issue still remains.

While using adb logcat and looking for nfc strings while I toggled it off and on I found that it appears that there is some issue with the NFC/Bluetooth radio handoff. I'm not entirely sure if it's a red herring or not. Just a message in the logs indicating there was some form of issue, but it only showed up once after a stock rom flash and rebooting the device and performing the same steps didn't emit the same message again.

I started looking at the init.rc and ueventd.rc files and noticed references to /dev/sec-nfc and /dev/bmc2079x - neither of which exist in /dev on my device. I didn't check when I first got the phone as I was under the false assumption at the time that it was hardware related. The /data/nfc directory and directories related to the libnxp-nfc and bmc nfc appear correctly and to my knowledge contain the correct firmware images and files required for the hardware to work.

I posted this same question on the galaxys5 subreddit over on reddit.com and there is one other user who has a 900F who has experienced the exact same issue. So it seems like it's not a oneoff issue. I'm just hoping to figure out what the issue is and if it can be fixed.

Any ideas on things I can look at beyond what I have already would be awesome.

Also, if anyone has time and can see if /dev/sec-nfc and /dev/bmc2079x device entries exist on their S5 that would be super helpful. If they do exist, then perhaps it points to the hardware simply not being initialized fully, that's simply a guess on my part. If you do happen to have those 2 dev files can you attach them so I can test them out? I would be forever grateful.

Cheers.