Currently recovery button invoke maskrom mode. In this mode, Armbian image could not be directly written to the storage (eMMC/SD). UMS mode is preferred.
There are several things to consider/need to be done,
ums and rockusb is broken on helios64
USB type C signals are shared between FTDI and SoC, U-Boot need to switch the USB MUX to SoC before entering download mode.
Staggering HDD Power rail currently implemented in device tree, so button press only readable after ~5 seconds boot. Better to move it to board file.
Provide visual indicator to notify user