Poor connectivity of mobile data after IMEI loss and reinjection

sxorpyon

New member
Jul 13, 2013
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Hello everyone, please excuse my noobness. I have spent two days now searching and trying to solve my issue, but no luck. Here are the series of events:

1. rooted i747 and got cwm 5.5
2. flashed liquidsmooth with cwm 5.5 and gapps
3. everything was fine (i think)
4. i tried to flash cm 10.1 with cwm 5.5 not realizing i needed 6.x and the flash failed
5. restored to my liquidsmooth back up
6. realized my imei was 0 at this point and no cell signal
7. used odin 3.07 to flash back to stock 4.1.1 rom from samsung
8. injected my imei using NV items reader writer method

After this sequence of events, regardless of the rom (stock, cm, liquidsmooth), my modem connects to LTE and is fine while i'm using it, but then after idling for 20 mins or more is on GPRS. Sometimes it has no data connection whatsoever. If i go to airplane mode and then come back out of airplane mode it will find the LTE tower and be fine again until I leave it alone or use it for more than 20 minutes.

I am using the correct APN (phone or pta on ATT)

my IMEI is correct under status in the about section in settings.

I have also done this : http://forum.xda-developers.com/show....php?t=2036891

i have also flashed my modem with this rom : I747UCDLK3_I747ATTDLK3_ATT (My baseband version is UCDLK3) from this thread: http://forum.xda-developers.com/show....php?t=1831898

The issue isn't that I can not connect to HSPA+ or LTE ... the issue is I lose that connectivity after 20-30 minutes and can not gain it back unless I toggle airplane on and off.

Any help or suggestions would be greatly appreciated.