My steps:
- Downgraded Google Pixel 4a 5G from Android 12 to Android 11 stock firmware12
- Installed /e/OS 1.5 r (Android 11) with Easy Installer
- Everything was working (bootloader locked)
- Start OTA Update installation of e-1.6-r-20221213242618-stable-bramble.zip / it was also offered https://ota.ecloud.global/builds/full/stable/bramble/e-1.7-r-20230110250404-stable-bramble.zip
- Reboot
- Boot loader is unlocked now
Maybe somebody has experience on this and can answer these questions:
Is that intended that the bootloader is unlocked after OTA?
How to avoid the unlocked bootloader after OTA?
How to lock the bootloader without doing a complete device wipe?