Larry Matter

Glad to hear that
 
The funny thing is that the kernel switching never worked for rk3399 family as it is a bit of a frankenstein...
After https://github.com/armbian/config/pull/127 is merged and published it should work as expected.

Ok, it needs one more change to fix the boot issue (besides working bluetooth).
Right now the service type is set to forking but the brcm_patchram_plus_rk3399 binary is not forking so systemd treats it as not successfully activated / activating.
 
Change Type to exec and it should be properly treated by systemd.
I adjusted it in the PR too: https://github.com/armbian/build/pull/2480/commits/92729573cea1aa786432e1dce42d641019e8bcd4

with your samsung ssd i would expect a bit more. Have you tried the 5.4 kernel? (check other download options)

just shared in another post on this forum my NVME iozone results for my Nanopi M4v1 with 1TB XPG SX8200 Pro.
800000+kBytes/sec both read and write.
specially for @NicoD some pictures. I power with 4a adapter. Self designed and 3d printed cabrio case, that does not fit well now with nvme board.

My results with a NanoPi M4v2 + 8A custom power supply + Samsung NVMe 250 GB EVO 960 PRO:
 
$ dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
16384+0 records in
16384+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 2.72603 s, 394 MB/s
 
Kernel 4.4.213-rk3399
 
Slow isn't it ? I wonder what can be done to improve this.
 

As root:
cp /etc/apt/sources.list /etc/apt/sources.list.backup sed -i 's|stretch|buster|g' /etc/apt/sources.list apt update && apt -y upgrade && apt -y dist-upgrade It takes awhile, and welcome to Buster.