Is it possible that A53 (little) can not run at the highest design frequency (1.51GHz)? I configured the A53 to 1.42GHz and the A72 to 1.8GHz, which looks good. I also have a NanoPi M4V1, it's running the official mainline kernel 5.9.1, and the kernel default configuration is 1.42GHz+1.8GHz, and I have never found stability problems.