Downloaded iode OS on Samsung Galaxy S9+ https://forum.xda-developers.com/t/rom-s9-s9-11-0-iodeos-lineageos-18-1-microg-adblocker-03-08-2021.4170059/#post-83610693 

- Download the custom ROM in laptop.

- Download TWRP image file in laptop.

- Enable developer options in the phone.

- Enable USB debugging.

- Unlock the bootloader in the phone.

- Power off the phone.

- Press Volume Up + Bixby button + power button all at once for around 10 seconds. A warning screen will be shown. click the button that the on screen instructions correlate to “Continue”, and insert the USB cable into the device. This will make the phone reach download mode. 

- Plug phone using USB to the laptop.

- Command enter: heimdall flash --RECOVERY twrp-3.5.2_9-0-star2lte.img --no-reboot

- Volume down + power key to power off.

- When the screen gets powered off, press Volume Up + Bixby button + power button. 

- TWRP screen shows up.

- click wipe -> format data. Back to wipe. Now go to Advanced Wipe and wipe -- Davlik, cache, system, data.

- back to the main screen of TWRP.

- Command to install the OS in root folder of the phone: 

adb push iode-2.0-20210729-star2lte.zip /

- Now in phone, go to TWRP main screen -> install -> find the file of the OS and install it. 

- Wipe cache and boot into recovery. 

- The OS should boot now and should be installed in your system.



How to get root access?

- Install magisk file in laptop from here https://github.com/topjohnwu/Magisk/releases - .apk file. And also download the same file by renaming it as .zip file.
- In phone, in developer options, enable advanced restart.
- Now restart your phone -> select boot in recovery mode.
- Now connect phone with laptop via USB.
- See if adb devices command is detecting your phone. If it detects your phone, then move to step 6.
- push the file into the phone using adb push command.
- Go to phone and in the TWRP screen -> Install -> install zip file and install apk file.
- Reboot system.
- After reboot, open any app which requires root access and magisk witll ask you permission to allow root access to that app.