[Miscellaneous Android Development] PeterCxy:
Introduction

This thread contains the LineageOS 17.1 custom firmware images for the Unihertz Atom L, a rugged Android phone released by Unihertz in July 2020, and the accompanying LineageOS Recovery used for flashing the firmware.

Please note that this ROM is one of my side projects, for which I could provide zero warranty. By installing this ROM, you acknowledge that you take all the risks that come with installing custom firmwares on your devices, including but not limited to bricking your device, losing your data, etc. You are always suggested to keep backups and make sure you know how to flash back to official ROM before trying any custom ROMs.

Please find the download links in the Download section. The following sections are guides to installing the ROM.

WARNING: DO NOT try to install this on Atom XL. This is ONLY for the Atom L.

Working Features

- All basic features (Telephony, VoLTE, Audio, Camera, NFC, WiFi, Bluetooth, ....)

- Programmable PTT (red) button (Functionality can be set in Settings - System - Buttons, under the "Search Button" section)

- 48MP camera seems to be working (unlike on many other super resolution devices)

Known Issues

- VoLTE is working (at least for me) but sometimes quirky. If you find it somehow stopped working, usually turning it off and back on again (in Settings - Network - Mobile Network) will fix it. Putting the device to SELinux Permissive mode also fixes most of the VoLTE quirks but this is not recommended (a few quirks in Enforcing mode is better than having the whole device Permissive)

Unlocking

1. Boot your Atom L to the official OS

2. Go into Settings - About phone, tap "build number" several times to enable developer settings

3. Go to Settings - System - Developer Settings, enable OEM unlocking and ADB debugging

4. Run `adb reboot bootloader` on your PC (there is no way to enter bootloader directly, only possible through adb)

5. Run `adb flashing unlock` and comfirm unlock on device (THIS WILL WIPE ALL DATA)

6. Reboot and now you should see an unlocked warning during boot screen.

Installing LineageOS Recovery

For now the only working recovery is the LineageOS Recovery, because the device's kernel does not load the touch driver in recovery mode for whatever reason, rendering TWRP useless.

1. Download `lineage_recovery_XXX.img` and `vbmeta.zip`, unpack `vbmeta.zip` to get three .img files starting with `vbmeta`

2. Run `adb reboot bootloader` to put your device in bootloader mode

3. Run `fastboot flash --disable-verification --disable-verity vbmeta vbmeta.img`

4. Run `fastboot flash --disable-verification --disable-verity vbmeta_system vbmeta_system.img`

5. Run `fastboot flash --disable-verification --disable-verity vbmeta_vendor vbmeta_vendor.img`

6. Run `fastboot flash recovery lineage_recovery_XXX.img`

7. Run `fastboot reboot recovery` to reboot into the newly-installed LineageOS Recovery

The LineageOS Recovery is operated by volume keys as selection and power as confirmation (or entering sub-menus). To return to upper levels of menus from sub-menus, press volume up until the selection goes to the first item and then disappears, then press power (i.e. there's a hidden "Go Back" item at the very top of each sub-menu).

The recovery will show a verification failed prompt for most packages that are not signed with the AOSP keys. This is safe to ignore.

Installing LineageOS 17.1

The LineageOS image must be installed via LineageOS recovery.

1. Download `lineage-17.1-Atom_L-XXX.zip`

2. Reboot your device into recovery (`adb reboot recovery` or simply hold volume up while turning power on)

3. Wipe all data (factory reset) (THIS DELETES EVEN INTERNAL STORAGE)

4. Choose Apply Update, then Apply Update from ADB

5. Run `adb sideload lineage-17.1-Atom_L-XXX.zip` from your PC

6. Wait for the process to finish. (The recovery might prompt something about verification failure, just ignore it and continue anyway)

7. At this point, you can then sideload the LATEST Magisk and OpenGAPPS Nano at your will (note that the size of the system partition might only be enough for the `nano` variant of OpenGAPPS) (If installing Magisk / OpenGAPPS fails, you can try rebooting into recovery again in advanced menus, then try installing them again)

8. Reboot into system and enjoy (Note that Magisk might cause your device to boot loop once or two but it will eventually boot)

When updating to a newer build, you have to flash the new zip, and then re-flash whatever mod you have installed previously (Magisk / GAPPS).

Download Links

LineageOS:

lineage-17.1-Atom_L-20200828-peter-signed.zip: https://mega.nz/file/bAgh1BZA#jzMs_0e9NUR9NcALXWp51ZeWttM5rl_3K5T8Or9hAW0

- Synchronized updates from LineageOS upstream.

lineage-17.1-Atom_L-20200728-peter-signed.zip: https://mega.nz/file/vBwlmL5D#wpw8RovBHyVFCLFlhQ2H5QAIb0ECXkT4of0FRijiP6A

LineageOS Recovery:

lineage_recovery_20200728.img: https://mega.nz/file/yc4Dnbyb#yx0Ci9p3q9_lfAiXkGfgWDFnRJI-JSGrv3kyawkU3fw

vbmeta:

vbmeta.zip: https://mega.nz/file/nF51mBoY#ZNY4j92wc_6a1dXch3l5r-w4VFl9QjN7YJaRMKRoEGk

XDA:DevDB Information

LineageOS 17.1 for Unihertz Atom L, ROM for the Android General

Contributors

PeterCxy

Source Code: https://cgit.typeblog.net/android/device/unihertz/Atom_L/

ROM OS Version: Android 10

Version Information

Status: Alpha

Created 2020-07-28

Last Updated 2020-07-28