TWRP device tree for OnePlus Nord 2T 5G (karen)

Basic	Spec Sheet
Codename	`karen`
Device name	`OP557AL1` (OnePlus Nord 2T 5G)
Model names	`CPH2399` "EU" global model `CPH2401` India model
CPU	Octa-core
Chipset	MediaTek MT6893 Dimensity 1300 5G (6 nm) (MT6893Z_Z/CZA)
GPU	Mali-G77 MC9
Memory	8/12 GB RAM
Shipped Android Version	Android 12.1 (OxygenOS 12.1)
Storage	128/256 GB
Battery	Li-Po 4500 mAh, non-removable
Display	AMOLED, 90Hz, HDR10+ 1080 x 2400 pixels, 20:9 ratio (~409 ppi density)
Camera (Back)(Main)	50 MP, f/1.8, 24mm (wide), 1/1.56", 1.0µm, PDAF, OIS 8 MP, f/2.2, 120˚ (ultrawide) 2 MP, f/2.2, (monochrome)
Camera (Front)	32 MP, f/2.4, (wide), 1/2.8", 0.8µm

BOARD_USES_RECOVERY_AS_BOOT

Keep in mind, karen has NO recovery partition. Recovery is part of the boot partition, so it takes care of normal boot and recovery.

SO MAKE SURE YOU HAVE A BACKUP boot.img

Building

Basic instructions. From there you'll need to research.

Get started with https://github.com/minimal-manifest-twrp/platform_manifest_twrp_aosp/tree/twrp-12.1

repo init -u https://github.com/minimal-manifest-twrp/platform_manifest_twrp_aosp.git -b twrp-12.1
repo sync -j5 --current-branch --no-clone-bundle --no-tags

Add this device tree to device/oneplus/karen.

mkdir -p device/oneplus
cd device/oneplus
git clone https://github.com/oneplus-karen-roms/android_device_oneplus_karen-twrp.git karen
cd ../..

Try an eng build.

export ALLOW_MISSING_DEPENDENCIES=true; . build/envsetup.sh; lunch twrp_karen-eng
make bootimage

You should now be able to flash out/target/product/karen/boot.img
```
cd out/target/product/karen
fastboot flash boot boot.img
```

Experimental builds

1. Flash just TWRP

https://github.com/oneplus-karen-roms/android_device_oneplus_karen-twrp/releases

Find the .img files under a releases' assets. And flash like normal. fastboot flash boot twrp-boot-xxx.img

2. Install the ramdisk

Boot into TWRP, then:

adb push stock-boot.img /sdcard/stock-boot.img (get this from an official OTA file).
adb push twrp-boot-xxx.img /sdcard/twrp-boot-xxx.img
Install the Stock stock-boot.img for your OS version. DO NOT reboot yet.
Install the ramdisk from /sdcard/twrp-boot-xxx.img. DO NOT reboot yet.
adb shell -> dd if=/dev/block/by-name/boot of=/sdcard/boot-plus-twrp.img (You will need this for rooting).
adb reboot

3. Rooting

Booting the phone normally:

Open the Magisk app.
Choose /sdcard/boot-plus-twrp.img to be patched.
Note the filename you get in the log /sdcard/Download/magisk_patched-XXXXXXX.img
adb reboot recovery

When rebooted to TWRP:

Install the file you got /sdcard/Download/magisk_patched-XXXXXXX.img to Boot.
Reboot! You're done!

oneplus-karen-roms / android_device_oneplus_karen-twrp