Develop Bugs

LTE Disabled + Random Signal Drop

Hey guys I need help,
I recently flashed loserskater's SRx3 TW based ROM for my i747 which went fine but I decided to revert back to an AOSP rom for overall smoothness. For those unfamiliar with SRx3 ROM, it comes with an AROMA installer which had one of the options indicating that if I wanted WiFi I had to use a specific kernel. So, naturally, I did. Well now after reverting back to an AOSP ROM, I'm noticing that LTE isn't connecting and that my signal continuously drops. Every 10 or so minutes my mobile signal will drop completely, not allowing me to make calls or texts. Also, when the mobile network is available I'm seeing H+ in my statusbar when normally I've been seeing LTE since I live in a really strong LTE network. I've checked the Mobile Networks section of settings and cannot figure out which one needs to be selected to re-enable LTE. HELP!

I have the same problem. A little less frequent than you though.

[Q] If my phone turns off for a long time, I lose ability to connect to 4g LTE

Hello, I'm pretty new to the custom rom world.
I am currently using latest Spirit AOSP cm11/kitkat based rom with the stock kernel that comes with this.
Now If i use the ND8 stock rom, there is no problem whatsoever with the ability to connect to 4g LTE.
But for some reason, when I'm on custom ROM and my device turns off for a long time / I disable my radio (when connected to wifi)--I'm not sure which one causes the problem--the phone just loses ability to connect to LTE.
I use two apps:
LTE Discovery
advanced signal status
advanced signal status lets me see if my phone can find 4g lte signal/how strong it is. When the 4g LTE is working, i get signals in -(number)db, but when it doesn't it just says n/a for all the sections.
with LTE discovery I use it to see what type of connection i get-- LTE when 4glte is working, and eHRDP? or evdo rev. A for when I can't connect to lte.
my APN settings are correctly set-- my phone has data, voice, and text-- it's just the LTE connection that gets dropped for seemingly no reason.
My method of fixing this is wiping data/cache/delvik/system, install stock kk nd8, perform SCRTN, make sure data/phone/text is working
then I wipe data and cache, then restore my rom... that is working..
If I restore to a point when lte was not working, lte will not work..
but doing this everytime my phone can't lte is very tiring..
I don't even know where to start troubleshooting this issue i have..
I don't even know if anybody has the same issue.. or even heard of anything even close to this.. please help

4G Disappeared

I flashed the Lollipop version of Liquid Smooth on my AT&T G3 and at first everything was working fine, 4G included. After a couple of days 4G disappeared. When this happened it didn't just go to 3G, it lost all data service completely. I originally figured it was the ROM and flashed back to the previous ROM I had using the TWRP backup I made beforehand. Same story, no data service. Figured maybe it was the modem so I flashed a working G3 modem on here, same story. I flashed to a different Lollipop ROM, Resurrection, to see if that fixed anything, nope. This is the ROM I currently have installed. At this point I went and look at the mobile network options and immediately noticed 1 issue, the preferred service was 3G and not LTE. I had an option to change it to LTE but when I actually select LTE it doesn't actually switch, it just stays on 3G.
The one good thing I managed to do was switch the APN to one that worked with 3G. The APN that was originally set was "pta", I can provide the actual APN information if that'll be useful but I figure most ROMs are going to have similarly named APNs. 3G works on at least 2 of the APNs listed for this ROM, "broadband" and "wap.cingular".
I called AT&T and determined that I my 4G service wasn't cut off; not that I really thought it was anyway as that wouldn't explain why I can't even select 4G as a network type. I'm kind of at a loss as to how I just randomly lost 4G access without actually making any changes to the firmware or OS of the phone. I'm also at a loss of how I can get it back.

And I am just sitting here with 3G with speed of 2 Mbps...

No one has any ideas or advice?

[Q] N900T: fixes for poor signal?

My N900T has much worse signal than my previous Note II - between 15 and 20 dBm worse, so essentially unusable out in the fringe area I live in.
I'm running SlimKat 9.0 (4.4.4) baseband is N900T UVUENK3 (which I think might be the most recent modem).
I'm using a StraightTalk ATT SIM (phone is unlocked) but that shouldn't matter for signal strength
I've got Preferred network type: LTE
And in service mode / phone info, I have preferred network type: LTE/GSM auto (PRL) - unchanged from standard.
I've removed the back cover (the one under the battery door) and made sure all the "fingers" make good contact with the contact pads that are built into that cover (fixed my GPS but not baseband)
Anything else I can check? Should I try some ATT radios to see if signal improves?
Or is this just the nature of the beast? Move to the city or get a different phone?
Thanks for any input!

Had this problem but hopefully the fix I used will work better. I flashed pac rom from nightly and resulted in no signal even though showed 3 bars(never higher or lower) but no connection in reality. Tried this and got signal kinda ( very slow and missed calls and sms)
Anyway
On tmobile network but might help either way idk never had att.
First goto
Settings/More Networks/...
Then first try the lte if not heard using 3g can fix signal connection with custom roms.
Check your apn settings and verify with att/simple talk
And if needed hit the mobile operators and let it do its thing.
Still not working can try fixing another way let me know.
Screens attached and can't post link ig but quick Google search should net you the setting. I did keywords "att apn settings"
Let me know how it goes. Flashing pac rom see how update goes this time for me lol

The signal got a good bit better when I replaced the antenna signal cable. Cost a whole $3.
I'm still 5 or 6 dBi down from my old note 2, but, from my forum reading, that might be the nature of this beast.

I have same problem, poor network, and sometimes when I go to some club or cafe I dont have network and on S2 same network I have full signal 3G, H+

G4 H815 doesn't stick to LTE - apn okay, lp&mm stock kdz already flashed

Hello!
I have a big problem with my G4 (H815 version, Germany) beginning with the switch from CM13 to the (stock based) Genisys 3.2 ROM. I've tried to fix it for three days now but without success. It doesn't stick to LTE anymore like it should do and did before. After a reboot it does sometimes connect to LTE but after switching back from wifi or airplane mode it's showing the "no signal" icon. Then it takes some seconds until it reconnects to the mobile network but now just to 2G or 3G. From this point it's not willing to reconnect to LTE, even not through the manual RAT-selection. "Force LTE" using the hidden menu then results in no network connection. However, after restoring my EFS-partition-backup with TWRP (from a time when it was working perfectly) it's connecting to LTE directly after boot but only once and only until you toggle wifi or go offline - like described before. After the next reboot it will mostly connect to 3G and then maybe switch to LTE sometimes or not.
Of course I have checked, deleted and restored my APN multiple times, I have also recovered to a stock V20b and V10d .kdz using LG UP in refurbish mode. Unfortunately even on the fresh and untouched V10d install it shows the same strange behaviour. Restoring the CM13 backup (including EFS partition), which has worked perfectly before, shows the same network bug now.
My sim-card is still working perfectly in my other phones. It still connects and reconnects almost instantly to LTE in my old S4 in places where the G4 did the same but struggles now.
I have even tried the cdmatool which is used to unlock additional LTE bands. I didn't change anything but it does show all usual LTE-bands which are needed for my provider.
Does anyone have an idea what I could try next? I'm living in an area with much better LTE than 3G connection and paying for a quite expensive LTE contract so a working LTE is very important for me. If I don't get that to work again I would need to replace my just over one month old G4 :crying:
Many thanks in advance for your answers
f-rouz

Meanwhile I have also tried another simcard. Still no LTE

i have the exact same problem, well, almost. no unlocked bootloader, but when i first got the phone i root injected the system.img and flashed away, thought everything was fine. now it just doesn't reconnect to 4G. well, at home at least. on my S4 i get 4 out of 5 bars on 4G, with the G4 i get 2 or 3 bars out of 5 on 4G, so the signal isn't great but good enough. i live in hastings (a town) and went to brighton today (a city) where the signal is max 4G, and the device does pick it up. but as soon as i go through a 3G area to home, it doesn't reconnect. have tried flashing original system.img back, upgrading to MM 6.0 after factory reset (via LG bridge), then downgraded again to V10c via LGUP - factory reset before the downgrade, no joy, still the same.
when you say you have forced LTE in hidden menu, did you try this - enter 277634#*# in dialer and go to field test > modem settings > lte band selection and select the band for your operator, which can be found on 'wiki europe lte bands'. there were two bands for my provider (three UK) and band 3 was what i wanted. i can now switch to 4G but it's a pain having to this every time i come home ( i use my phone for home internet via tethering).
worst part is, having refrained from unlocking the bootloader to save the warranty, i phoned LG today to send it back as faulty and explained i could switch it to lte band 3 via the hidden menu and they told me my warranty was now invalid as had OPENED the hidden menu (they told me this after taking my imei). so if anyone reads this and phones LG for a repair, don't tell them you have accessed the hidden menu if you have done what i did.
think i'm just gonna sell the phone, make a palpable loss and buy another one, as i love the phone

Wow, I haven't thought that from LG. I feel like I've searched the whole internet already and nobody has a solution to this problem. I'm about to send my G4 back to Amazon (or sell it otherwise), hope the best and get myself a Oneplus Two because the G4 seems to be too *****y from the development standpoint. I've never had a situation like this with my previous Samsung phones since 2009. I will miss this camera though. And the NFC and the wireless and fast charging capability... the G4 is a nice phone nevertheless...
Edit: And yes, I have tried the "277634#*#" hidden menu, although it isn't accessible through this code on MM any more (you need a terminal command to start this).

Have you tried limiting it to 4G/2G in hidden menu? Mine also have a similar problem in Lollipop in that it is very aggressive in dropping to 3G. That worked for me. Phone doesn't drop to 2G much provided you have decent LTE coverage.
Now I'm on Marshmallow and not rooted, thus cannot do the same. Though it seems to be sticking to LTE a bit better than before.

I have tried that but it doesn't work. As I don't get any network connection wenn forcing LTE only, forcing LTE/2g results in 2g only.

My G4 still doesn't want to connect to LTE so I have ordered a S6 now... As I still have no idea what was causing this I just can't risk that happening again. It has been a short journey for my first LG and me and I really liked my G4 actually... Bye G4 community

you just needed to flash the stock modem, most likely

Unfortunately, it isn't that easy. That was of course the first thing I did (and not just one time)...