This thread is based on my original post found in the AT&T G3 Lounge Thread..
What's new is I've just packed 20F into a flashable zip for those with TWRP already installed. It's not much.. but I know many would prefer not to use ADB or terminal.
What's this thread have to offer?
Flashable/BUMP'd D850 20F "rom" (system/boot)
Flashable D850 20F modem
Stock D850 20F partition images
Patched/BUMP'd D850 20F boot.img
Manual directions for installing TWRP if already on 20F
Manual directions for installing 20F if flashable zips aren't your thing
The above mentioned can all be downloaded HERE ON CODEFIRE
Flashable "rom" directions:
1. Put D850_20F_Lollipop_Stock.zip and D850_20F_2.0.1.c1.13-00050_Modem.zip on sdcard
--For root: Also grab the SuperSU zip from Chainfire HERE
2. Boot into TWRP
3. Hit install button and select each zip file you need
4. Swipe to flash... done. Rom flash will take a bit.. be patient.
5. Reboot phone when rom, modem, root is flashed. First Lollipop boot may take up to 5 minutes.
In some cases you may need to wipe cache/dalvik/data(factory reset) in TWRP if the phone gets stuck on boot animation or if things just aren't acting right. To avoid data loss be sure to use something like Helium or Titanium Backup prior to upgrading to Lollipop. TWRP backups/Nandroids don't hurt either.
Having issues with internal sdcard permissions afterwards? Having issues with downloads not saving? You may need to fix your sdcard permissions. In terminal emulator or adb shell enter:
restorecon -FR /data/media/0/
Below I am including my original directions for manually flashing Lollipop.. whether completely stock and already on 20F... or already rooted/BUMP'd/TWRP'd.
You do not need to pay attention to any of this below if you are just flashing the rom above... these are the original manual directions only. #learn2read
If you want TWRP just downgrade aboot.img and laf.img to KK.. then BUMP'd TWRP will work. Must be rooted to be able to flash TWRP obviously. If not already rooted -- Root with THIS METHOD HERE or use THIS ONE-CLICK METHOD if typing an ADB command scares you.
If rooted and on stock 20F Lollipop follow #1
If already TWRP'd/BUMP'd on KitKat (or using AOSP) and want to manually update to rooted stock 20F follow #2
Download D850 TWRP HERE and rename to twrp.img. download stock KK aboot and laf images HERE. Stick all 3 on root of internal sdcard. You'll also have to flash a patched stock 20F boot.img so that the Lollipop system still boots when using the downgraded aboot.img/laf.img. You can download the patched boot.img HERE. Stick it in the root of your internal sdcard.
Now issue the following commands with ADB shell. If using terminal app on phone do not use the "adb shell" command:
adb shell su md5 /sdcard/aboot.img (confirm md5 = 348064a6d4f8d5b7d3eeec79d86de5bd before proceeding) dd if=/sdcard/aboot.img of=/dev/block/platform/msm_sdcc.1/by-name/aboot dd if=/sdcard/laf.img of=/dev/block/platform/msm_sdcc.1/by-name/laf dd if=/sdcard/twrp.img of=/dev/block/platform/msm_sdcc.1/by-name/recovery dd if=/sdcard/patched-20f-boot.img of=/dev/block/platform/msm_sdcc.1/by-name/boot
If already TWRP'd/BUMP'd and you want to upgrade manually to 20F Lollipop... download the patched boot.img HERE and stick it on the root of your internal sdcard.. along with the 20F modem.img and system.img. (@timmytim shared system.img in the lounge thread HERE so be sure to thank him)
You may or may not have to "factory reset" in TWRP. YMMV.
[If flashing system.img you must be in TWRP, not the rom, while issuing these commands]
[May need the "Koush Universal ADB" drivers to get ADB goin' in TWRP]
adb shell su dd if=/sdcard/patched-20f-boot.img of=/dev/block/platform/msm_sdcc.1/by-name/boot dd if=/sdcard/modem.img of=/dev/block/platform/msm_sdcc.1/by-name/modem dd if=/sdcard/system.img of=/dev/block/platform/msm_sdcc.1/by-name/system