[Questions and bugs regarding the HC2]

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!!