Fresh install of Armbian_21.05.1_Rockpi-4b_buster_current_5.10.35
Ran apt update/upgrade
Reboot
arm-config>softy>install linux headers
It seems to be affecting the latest release only. Tested with Armbian_21.02.3_Rockpi-4b_buster_current_5.10.21 and it works until it's upgraded. I also tried disabling kernel upgrades before upgrading and still received this error.