My attempts to install /e/OS ‘S’ v1.6 on the Google Pixel 4a 5G (bramble) and Pixel 5 (redfin) have failed. Both times I could not boot into /e/ recovery mode after flashing vendor_boot recovery-e-1.6-s-*. Each time the devices booted into fastboot mode. In the upper right corner the devices showed “Start”.
Two other installations with other CustomROMs based on Android 12 were performed flawlessly and without any problems.
On the Pixel 5 (redfin) with a custom ROM fork of LineageOS code, I was even able to relock the bootloader again in another installation process, since an avb_custom_key' is available.
The source of the error must be in the /e/OS file vendor_boot recovery-e-1.6-s-*
.