I did some experiments about topic issue.
I did play with Cubieboard 1 and 2. Cubieboard 1 works fine with Armbian 5.2.5.
Cubieboard 2 has starting problem on both Armbian 5.3.5 and 5.2.5
I do not use HDMI interface. I'm just using serial interface with USB - COM. I have used different scenarios to reproduce this issue.
BTW I have loaded Cubeez on EMMC.
1. If I'm trying to start from SD card after Cubieboard 2 was unpowered and serial interface unconnected during 10 or more minutes - board unstarted.
2. I start with Cubeez from MMC - board started. After that I put SD card to board and just repower - board started with Armbian good. I can wait a few seconds or few minutes between power off and on and Armbian start good. If board powered off but USB - COM connected, looks like we have powered CPU through contacts TX and RX. And board will started good from SD card even if more period of time power supply unconnected.
So looks like some data keeps holding in memory...