I got my HC2 yesterday and am quite satisfied with it.
I'm using the latest Armbian Stretch release.

The spin-down of my 3TB WD Red was solved by a firmware update.

Unfortunately there are still some errors in the error output (journalctl -p 3).
Maybe you have a hint how I can solve it:
 

Nov 03 18:16:42 NAS kernel: CPU4: Spectre v2: incorrect context switching function, system vulnerable
Nov 03 18:16:42 NAS kernel: CPU5: Spectre v2: incorrect context switching function, system vulnerable
Nov 03 18:16:42 NAS kernel: CPU6: Spectre v2: incorrect context switching function, system vulnerable
Nov 03 18:16:42 NAS kernel: CPU7: Spectre v2: incorrect context switching function, system vulnerable
Nov 03 18:16:42 NAS kernel: devfreq devfreq0: Couldn't update frequency transition information.

No idea? What causes this error?
 

Nov 29 22:39:09 NAS kernel: s5p_mfc_load_firmware:73: Firmware is not present in the /lib/firmware directory nor compiled in kernel

Error still occurs after:
 

apt-get install -y firmware-samsung
mkdir -p /lib/firmware/s5p-mfc
cp /lib/firmware/s5p-mfc.fw /lib/firmware/s5p-mfc-v6.fw  /lib/firmware/s5p-mfc/

Are there any stability/performance differences between the Armbian Stretch release and the official Ubuntu 18.04 release from Hardkernel?

Best regards!!

These messages are caused by the efforts to mitigate spectre issues.
Because  the HC2 (as well as my HC1  ) utilizing a enyxos processor ( belonging to the big.Little ARM achitectures ) it is affected by this kernel changes.

 

Regards,

Joe