[G4 General] duraaraa:
Note: The title of this guide is Enabling LTE bands, but actually, it's for LTE and for HSDPA bands.

This is something near and dear to me, as I travel the world somewhat and really prefer to have only one phone.

I spent all day figuring out how to add more LTE bands to this phone (I have a bootloader unlocked H815, European version, so please understand that it may not work with other versions, and simply can't even be attempted until you can root it.)

The model I own comes with the following bands:

2G bands	GSM 850 / 900 / 1800 / 1900

3G bands	HSDPA 850 / 900 / 1900 / 2100

4G bands	LTE band 1(2100), 2(1900), 3(1800), 4(1700/2100), 5(850), 7(2600), 8(900), 17(700), 20(800), 28(700)

I noticed, however, in the hidden testing menu (277634#*#, Field Test, Modem Settings, Network Mode), the following extra bands, none of which worked:

WCDMA 800, WCDMA AWS (1700/2100)

Along with the following extra LTE bands(277634#*#, Field Test, Modem Settings, LTE Band Selection), again, none of which worked:

Band 12, 13, 25, 29, 40

The result?

Having enabled all of the LTE bands available in the testing menu, I was able to add WCDMA 800 and AWS bands, along with LTE band 40. Unfortunately at this time, Bands 12, 13, 25, and 29 do not work, even if enabled. However, a T-Mobile radio file might help for band 12 if it's a radio issue, or it could be a hardware difference in which case there's nothing we can do. I really don't know until I can test with it. I'm happy about the extra bands, though, because in the US I use T-Mobile, so AWS helps, and in Japan, band 800 is used. Maybe I'll use 40 if I go to China some time.

So how to actually do this?

Step 1: Unlock bootloader and root. You can find out how to do that in other threads.

Step 2: Install the LG USB Drivers. It comes with the LG PC Software.

Step 3: Download CDMAtool from here: http://cdmatool.com/ A free trial works fine for this.

Step 4: Make sure you have adb, and connect your G4 to your PC. In an adb shell, execute the following:

su

echo 1 > /sys/devices/platform/lg_diag_cmd/diag_enable

Step 5: Unplug and re-plug your USB cable. Your phone is now in diag mode (although you wouldn't know any better because you don't get any special device names in Device Manager.)

Step 6: Open DFS which you downloaded from CDMAtool.com Deal with making an account, etc. as you have to get into the software. Close the account window and the actual software will launch.

Step 7: Double click your device to put a checkmark by it in DFS.

Step 8: Click the Band tab. Choose RF BC Config at the bottom. Then, choose read.

Step 9: Make sure your bands are displayed. Check the extra bands you want to add. I recommend against enabling bands other than those mentioned in this thread, but you can try at your own risk (in fact, I'd be interested to see if any work!)

Step 10: Click Write.

Step 11: Click the LTE tab. Click Read. Check the bands you want to add, click write. Then, choose LTE BC Config DIV LTE #6829 at the bottom and repeat the process again there.

Step 12: Sometimes the write doesn't go through, and I have no idea why, but I found it helps to play with your phone for five minutes after writing. Also, I found that even if you're not changing bands, it's somehow necessary to flash HSDPA and LTE bands both in one go before restarting the phone. Otherwise strange things happened like losing bands. I was able to get them back though by re-flashing.

Step 13: Reboot your phone and pray.

Step 14: Go into the hidden menu and test the new bands. If they work, you will see SUCCESS when you press them in the test menu. (277634#*#, Field Test, Modem Settings, Network Mode/LTE Band Selection)

I hope this is useful to any other globetrotters!