Armbian_26.2.1_Rock-3a_trixie_current_6.18.8_minimal.img.xz (ROCK3A) - system has NVME inserted and SATA M.2 E-key adaptor where HDD is connected to - SPI has Armbian legacy U-Boot, but that is skipped as SD-card with new image is inserted - further only power, ethernet and serial console cable connected: 1st boot and user creation all fine - network up, WAN IP shown - NVME is available (but OS is running from SD-card for the test) - SATA is not available as not supported mainline based kernel (and needs adding overlay manually when vendor kernel) - reboot does not reboot (but 'echo 1 > /proc/sys/kernel/sysrq ; echo b > /proc/sysrq-trigger' works) - also poweroff is only shutdown, no powerdown (and HDD keeps also spinning)

At this point you seem to have done everything properly. The next step would be to find the uart connection point on you board and hook up a usb-uart reader so you can see the debug output from uboot to see what is happening.

That is enabling multiboot (what enabled either Armbian or android to boot. I'm going through with you all the basics that you didn't mention in your original post (and that others often forget to do), to eliminate all the basic things. You say "maintain it", but you shouldn't hold that button too long, a few seconds (10 at most is all you need). Holding too long will not work.

Armbian_26.2.1_Bananapi_trixie_current_6.12.68_minimal.img.xz (Bananapi M1) - only power, ethernet and serial console cable connected: 1st boot and user creation all fine - network up, WAN IP shown - then connecting a SATA SSD ('hotplug'), pops up in dmesg, so recognized OK

I follow this instructions The reset button in the case of my box is inside Av connection, I already boot the images with press the button and maintain IT. The result is a screen with HKSERIES screen, I can wait one hour nothing happens only the image. A video to you see that I press the reset multiboot button. Thanks.