I noticed a change from: rk3399-sd-friendlycore-lite-focal-5.10-arm64-20211029.img to rk3399-sd-friendlycore-lite-focal-5.10-arm64-20211202.img.

With rk3399-sd-friendlycore-lite-focal-5.10-arm64-20211202.img the system is very slow. kworker/0:0H-mmc_complete is using a lot of CPU.