I fixed it
I can't say whether or not @mackdaddy57
's suggestion helped, but I did reset my network settings anyways (##72786#) because I think the key to making things work is starting with a "clean slate". Anyways, I've gone from having low speed 3G data and an intermittent connection to having very high speed LTE with support for (fast) MMS, and it does not seem to be dropping at all. Here's how I did it. My Preferred Network Type was set to "Global" from the beginning and thus through the duration of this.
You'll want to download my attachment and rename it to apns-conf.xml
. I got it from here
and it works great for this process without modifying it at all.
Now take that file and inject it into /system/etc of a pure stock ROM. I used this one: link
(KOT49H Deodexed) then put this modified ROM on your /sdcard
Follow mackdaddy57's instructions above. I actually skipped the setting of my MDN and MSID because I've never really had a problem with HFA and I was too scared to. I used Hidden Menus and executed the option labelled ##72786#. I then rebooted my phone and my signal was kaputz. I think it's important to be already running a custom ROM that you know doesn't have working data for this part. Maybe it's not.
Now reboot into recovery and flash the Stock ROM with the modified apns-conf.xml. Start up your phone, choose your language and now wait for it to activate. If you're in an LTE area you should see the letters over your signal bars within a minute. Just do not
Bypass the Google stuff. If I'm correct with my assumptions, at this point your phone is still kinda configuring itself. You should try to send an MMS as quickly as possible during this time. For me, an MMS failed the first time after 5 minutes, failed the second time after one minute, and was successfuly sent and received the third time after another minute. Every MMS after this didn't take long at all to send. If this sounds weird it's because it is.
I would suggest just giving your phone some time to "figure itself out" now. If your data seems solid, all that's left to do is flash any custom ROM you want, but be sure to use the modified apns-conf.xml from first boot.
This means either injecting it into the ROM zip or flashing it after flashing the ROM. I made a backup with APN Backup & Restore
and I'm leaving it on my /sdcard just in case I happen to muck that up someday but I don't know if that alone will work.
Looking forward to your feedback.