ingenium

They probably do have roaming agreements with GSM carriers in other countries. But you're better off just getting a local SIM and popping that in. Sent from my SPH-L720 using Tapatalk

I posted on their support forum about a week ago telling them the issue and giving them site IDs. Never got a response. But yeah I should call them as well and open a ticket. Sent from my SPH-L720 using Tapatalk

Has anyone else noticed issues with 1x 800 in the area? In Emeryville ever since they turned on 1x 800 around Thanksgiving, my call quality has been horrible (cutting out constantly) and texting very unreliable (get stuck sending, sending multiple copies, etc). I have a non-triband Galaxy S4, so it's not a CSFB issue. I verified that calls were indeed using the HD voice codec as well. I modified my PRL to prioritize 1900 over 800 for SID 4183, and the problems went away. My phone is connecting to the same towers as it did for 1x 800 according to Signal Check Pro. So the only difference is 1900 vs 800. Is anyone else seeing this? What could be the reason for it? Sent from my SPH-L720 using Tapatalk

The network may just move the phone to 800mhz for some reason. Or it's prioritized in the PRL. It seems some official PRLs keep 1x 800 and 1x 1900 at the same priority, but my current stock PRL has 1x 800 at a higher priority than 1x 1900. So I always connect to 1x 800 even if it's a weaker signal than 1900 (800 is only on some of the towers in my area). I do notice that 1x 800 seems to cut out more during calls, even with a signal stronger than - 78db according to Signal Check Pro... Not sure why this happens, but I get better call quality on 1900. Sometimes the 800 signal is practically unusable with the audio cutting out a lot, but my phone usually switches over to 1900 after a minute or so on the call if 800 is too weak. So it's not necessarily a bad thing your phone is using 1900, sometimes it's actually better. Sent from my SPH-L720 using Tapatalk

So does that mean if Sprint's version of the Galaxy S5 ends up having a Snapdragon 805 that it will, at least eventually, be able to use LTE-A and/or carrier aggregation?

I haven't noticed speed issues, but I've been having SMS issues (my roommate has the same issue, different phone). Basically texts get stuck sending. You can try resending it all you want but it won't send unless you change it somehow. Just adding an extra space somewhere is enough to cause it to send right away. It's been happening for about 2 weeks now, pretty frustrating. Sent from my SPH-L720 using Tapatalk

Does anyone know why some towers have 1x 800 but haven't had LTE added yet? There are quite a few in Emeryville, west Berkeley by the freeway, and Oakland near MacArthur BART that have 1x 800 but no LTE. Is this just because they haven't upgraded the backhaul yet for some reason?

The issue is that the nearby towers are broadcasting at 800Mhz. The current PRLs (as of 54016/55016/56016) always prioritize 800Mhz over 1900Mhz, so it won't switch to 1900Mhz unless the 800Mhz tower tells it to, or the signal is non-existent (like how the phone hangs onto a Sprint signal until it can't anymore before roaming). Airaves seem to only broadcast a 1900Mhz signal. There's a rumor that a software update is being pushed out (though it has supposedly been pushing "soon" since August...) to make it broadcast an 800Mhz beacon telling the phone to switch to 1900Mhz, but to my knowledge this hasn't happened yet. I ended up modifying my PRL to put my airave at the top of my region above the 800Mhz towers (http://s4gru.com/index.php?/topic/2440-airave-evo-4g-lte-data-connection-but-not-voice/&do=findComment&comment=60555) and it worked great. If you use that guide, be sure to get the correct info for your airave and local towers (I used https://play.google.com/store/apps/details?id=com.blueline.signalchecklite). On the Galaxy S4, you don't even need root or the MSL to write the PRL, it can be stored on the SD card and written using a hidden interface. Other phones may be similar.

OK, so I've verified that 850MHz WCDMA/HSPA+ indeed works, but you have to force it. For some reason it really wants to use GSM/EDGE. I had to go into the Testing service menu (normally *#*#4636#*#* in the dialer, but Samsung disabled it. I used a Nova Launcher shortcut, or there are apps in the Play Store to access it) and force it to only use WCDMA (selecting WCDMA preferred doesn't work, it will still choose GSM over WCDMA). That all said, I wasn't able to get SMS working for some reason. I could receive messages just fine, and make and receive phone calls just fine, but I got an error any time I tried sending a text. In the attached screenshot I was trying to activate a higher speed data package. I think it may have had something to do with the carrier though (in this case the Costa Rican carrier Kolbi), because I put the SIM in my 3G Nexus 7 and installed an SMS application and got the exact same error. I read that the usual reason was the Message Center/SMSC wasn't set properly, but I verified that wasn't the cause.

Oh nice! I hadn't seen your post about the build.prop edits. It worked flawlessly for me. I use Nova Launcher rather than the Touchwiz launcher, so I was able to add a shortcut on my homescreen to access the APN settings with the Sprint SIM in. I can switch between any of the 5 built in Sprint APNs (4 domestic, 1 for global roaming), and the ability to add new APNs is no longer greyed out. Thanks!

What ROM were you using? Just stock rooted, or one of the customized ROMs?

Just updated to MF9, and the APN settings are still greyed out.

Those are the system APNs, the ones that come pre-configured and will remain after a factory reset. When the user adds an APN it can't be stored in that file since it doesn't persist with a factory reset (and I believe /etc is mounted read-only). It appears that there are 2 locations for APNs, one for system provided APNs and one for user provided ones. I THINK that /etc/apns-conf.xml is used to initially generate /data/data/com.android.providers.telephony/databases/telephony.db. On my Nexus 7 at least, when I manually added an APN it showed up in this database and not /etc/apns-conf.xml. The question is though will just adding the APN to this database be sufficient for it to show up and be used? I think it is, but I won't have the opportunity to test it until the end of the month. I'll be traveling to a country with UMTS/HSPA 850, so I'll report back if I was able to get data to work.

I found a sqlite database file that looks like it has the APN information in it. Would it be possible to just edit this (with root) and add the APNs manually? I don't currently have a 3rd party SIM and I'm in the US, so I don't think added APNs would even show up in the list if the MCC/MNC doesn't match a signal it sees. The file in question is /data/data/com.android.providers.telephony/databases/telephony.db