[Verizon Motorola Droid Turbo Android Development] firstEncounter:
This is only for devices currently on 4.4 or rooted 5.1 w/ moforoot. This upgrade path allows moforoot to continue to work, and retains the ability to downgrade to 4.4.

Note 12/2/2015:

Development on this has been discontinued with the release of the SunShine bootloader unlock.

To use SunShine without having to deal with KingRoot, you can flash the Rooted v3 system img and then use SunShine to unlock. This is the most stable method if you can use mofo.

After unlocking using SunShine, please flash the latest bootloader/radio images from here. This will bring your phone completely up to date and provide a more stable experience with custom ROMs.

These images are still flashable after unlocking your bootloader if you'd like a stable, closest-to-stock ROM possible.

Instead of using mofo to flash the system image, you can just use

fastboot flash system filename-goes-here.img

You can then flash your own tweaks like Xposed.

I'd recommend making a back up of the stock ROM in TWRP so you have a stable base to go back to if anything goes wrong.

Note 10/10/2015:

Updated all images to the latest OTA update (SU4TL-44) and included the latest official Xposed version (v75) in extras v5.

Follow the instructions with 5.1_images_v4.zip to flash the updated firmware images.

Note 9/5/2015:

Updated extras (v4) to include the latest official Xposed version (v73). Read the previous note for more information.

Note 8/31/2015:

Updated extras to the latest official Xposed version (v72). Reflashing all of the images is not required, only the extras system.img using mofo.

You can download the full extras image (1.5gb), or if you already have the rooted v2 image, use the extras v3 patch (8mb) with the instructions below.

Using the rooted v2 image + patch will allow you to update in the future without redownloading the entire image (as long as you keep the original after patching).

Note 7/23/2015:

Updated to the latest OTA (23.11.39). Make sure to follow instructions and reflash all images from the latest zip.

Unfortunately, I couldn't provide a patch to go from rooted image v1->v2, so a redownload is needed.

When applying the latest extras, make sure you're applying it to the rooted image v2.

Files (updated 10/10/2015 w/ latest OTA & extras v5)

5.1 firmware images (v4)

SHA1: 8be8a19664e6ba5aa556838bb3f744cdbf41f2ef

Stock 5.1 system image (v3)

SHA1: 1e67fc22331f035e9f3bd6c28d81fb173dd86a3e

Rooted 5.1 system image (v3)

SHA1: b8ff04d7f6ad9de31292cf62da94a3d80d3e373c

Extras 5.1 system image (rooted v3 + extras v5) (see below for details)

SHA1: 126744919f86132c05d15e79373ea759f74e37cf

Instructions

A data wipe is not required, but please back up any important data beforehand in case something goes wrong.

After extracting 5.1_images_v4.zip, reboot into bootloader and run the following commands to prepare your phone for the latest 5.1 system image:

fastboot flash logo logo.bin
fastboot flash boot boot.img
fastboot flash modem modem.img
fastboot flash mdm1m9kefs3 fsg.mbn
fastboot erase mdm1m9kefs1
fastboot erase mdm1m9kefs2
fastboot flash recovery recovery.img
fastboot erase ddr
fastboot reboot-bootloader

Then use mofo to flash the system image of your choice and reboot.

After flashing a system image, the first boot will stay on the Motorola logo for an extra 30 seconds to 1 minute. This is rebuilding the cache partition (erased by moforoot after every flash).

If your phone doesn't boot after 5 minutes (and isn't showing the "Upgrading apps" dialog), try formatting the cache in recovery by doing the following:

While phone is off, hold the volume down button and turn it on to boot into bootloader. Use the volume keys to find the recovery option and press power to confirm.

Once you see the dead Android (it may also say "No Command", this is normal), pull up the recovery menu by holding power and pressing volume up (5.1 recovery is different than 4.4) and use the wipe cache option.

If the screen is blank in recovery with a periodically flashing Android icon, try booting the phone normally and trying again. This happened to me a few times, and I theorize it's because of the cache partition not being formatted after erased.

Extras (updated 10/10/2015 w/ latest OTA & Xposed official v75)

Download patch (v5)

SHA1: 451be2eef3df509facf16b807c6fc665c8fac090

If you don't want to deal with patching the image using xdelta3, you can download the full extras image in the Files section above.

This will prevent you from updating without redownloading the whole image in the future, but is easier for less experienced users.

Current extras:

Xposed official v75 (download APK from here)

(optional) ad blocking

busybox/sqlite3

tethering enabled

To apply the patch, use the rooted v3 image (not an already patched image) as a base, and follow the patching instructions (using xdelta3) in this post.

After patching the system.img with the extras, you'll use mofo to flash the patched image.

To use ad blocking, download AdAway (available in F-Droid) and enable it. Make sure the "Target hosts file" is set to "/data/hosts" in settings.