[Moto Maxx Android Development] ChazzMatt:
First, really strange that the clean modem status file nor re-flashing radio helped you at all. Very strange. One thing you said confuses me.

You say you have an XT1225..

But you also said this:

All Verizon Droid Turbo XT1254 stock firmware starts with "SU". No Moto Maxx/Moto Turbo stock firmware starts with "SU". (On that list, "RETEU" is for India Moto Turbo XT1225, by the way. "SU" is all the Verizon Droid Turbo XT1254 firmware.)

http://www.filefactory.com/folder/f9d1880e6c5b4800/?sort=created&order=DESC&show=50

If you flashed any Motorola firmware (bootloader, radio, anything) for Verizon Droid Turbo XT1254 onto an XT1225 -- or vice versa -- maybe that's why your phone is messed up? Or do you have Droid Turbo XT1254? That's what's confusing me. I pointed you to XT1225 radios because that's what you said you have. (With unlocked bootloader, stock XT1225 firmware is compatible with all XT1225; they all have the same FCC ID. And with unlocked bootloader, all XT1254/XT1250 stock firmware is compatible with XT1254/XT1250, as they share the same FCC ID. But XT1225 is not compatible with XT1254/XT1250 stock firmware.)

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Answer this question: on the back of your phone, at the VERY bottom right hand side, there's some faint lettering. You will see an FCC ID. Is the last number a "1" or a "2"? That's the fastest way to tell which Quark you have.

The XT1225 and XT1254/XT1250 all share LTE bands 2, 3, 4, 7.

The XT1225 additionally has LTE band 5 and 17 (more bands used by AT&T).

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FCC ID IHDT56PK2

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The XT1254/XT1250 instead has LTE band 13 (Verizon LTE band), plus CDMA bands. While it does have some HSPA bands, there's not as many as in the XT1225.

FCC ID IHDT56PK1

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There's no concerns going back to stock firmware as long as...

1) you don't try to flash an older bootloader than you already have, and

2) choose stock firmware that's compatible for your model (any XT1225 firmware for XT1225; any XT1254 firmware for XT1254/XT1250).

For instance, over in the Droid Turbo forum some people flashed newer radio/bootloader packages (which were in the same zip file) and forgot they were also flashing a newer bootloader... Then, when going back to Lollipop or something, bricked their phones because they were flashing an older bootloader. So, when going back to stock omit gpt.bin from the ADB flash commands, just in case. I also don't want you to brick your phone. ;) With an unlocked bootloader, you can go all the way back to Kitkat if you wish -- as long as you omit gpt.bin from the ADB flash commands.

BUT after going back to stock, do NOT take any OTA updates! That's another danger of going back to stock, sometimes you go back to a point (like Kitkat or Lollipop) where Motorola was still offering updates and your phone thinks you are eligible for an update. No, you still have a newer bootloader (possibly) under that "older" software, and you can't flash any partial OTA updates which contain another bootloader older than what you already have. Even though they may be on Kitkat, they still have a Marshmallow bootloader underneath. And they may not even know WHICH Marshmallow bootloader they have! So, always leave out the gpt.bin command and NEVER take OTA updates after going back to stock. (Any real OTA updates will be offered in the XDA forums anyway, in a manner that can be safely flashed.)

This advice is not just for you but for anyone reading.