https://grapheneos.org/install/web
Have a high quality USB C cable available. Don't cheap out.
Tap build number repeatedly to become a developer.
Settings > About phone/tablet
Enable OEM unlocking.
If greyed out, update device OS before beginning.
Hopefully it won't be greyed out after update.
Search settings for update --> update the system...
OEM unlocking available now! Yay.
If on Linux be sure to have android-skd-platform-tools-common installed
Also, stop the fwupd service --> sudo systemctl stop fwupd.service. It will restart on reboot
Start the device holding down the volume down button until you see the red "fastboot mode" screen
Plug in the usb and check 'Unlock Bootloader" button on screen. Confirm on device with power button. Computer screen shows bootloader unlocking triggered successfully.
Download the release --> wait patiently
Flash release --> wait patiently
Lock bootloader --> no waiting, just smile
Confirm on device with power button.Press power button again --> device restart with Graphene OS..
Feel like a hero.
