GS290: after installing /e/OS, BT and WiFi do not work

See also this GS290 easy-install worked well; Bluetooth & WLAN fail under e OS.

After installing /e/ on the GS290, there are repeated error messages of Bluetooth stopping. Both BT and WiFi do not work. In Settings > About Phone, it says "Wi-Fi MAC address unavailable".

Before installation, I had upgraded the stock Android on the GS290 to "Gigaset_GS290_10.0_V10_20211202_20211202-1156".

The solution was to revert back from /e/OS to stock Android, then upgrade Android to "Gigaset_GS290_10.0_V08_20210513_20210513-1335". So not beyond V08. Then install /e/OS. Problems solved.