Hey, just solved the same issue yesterday evening (bricked nanopi v1 after kernel update last sunday).
Here is what I did to solve it:
create a SDCard boot disk
plug the SDCard and boot with it (it will bypass the eMMC card)
set the root password and you should be able to ssh into it
mount the eMMC filesystem rw
chroot in the mount (lol) - with the right folder binded before (proc & sys)
wget some files - for me it was those 3:
linux-dtb-legacy-rk3399_21.08.2_arm64.deb
linux-headers-legacy-rk3399_21.08.2_arm64.deb
linux-image-legacy-rk3399_21.08.2_arm64.deb
from here: http://mirrors.netix.net/armbian/apt/pool/main/l/linux-4.4.213-rk3399/
(the new ones were still in /var/cache/apt/archives so I knew which ones were upgraded - and for some reason, I was unable to use apt-get in the chroot, that's why I had to download them directly - and I choose those versions because I thought that going back to the previous versions was enough)
dpkg -i those files
halt the nanopi and remove the SDCard
restart and voilà
I installed manually the linux-libc-dev package once booted with as I couldn't find it for downloading:
# sudo apt-get install linux-libc-dev=21.08.2 -V
To be sure that those packages will not be upgraded with future upgrades, I put a hold on them with "apt-mark hold":
# apt-mark hold linux-libc-dev linux-dtb-legacy-rk3399 linux-headers-legacy-rk3399 linux-image-legacy-rk3399
# dpkg -l | grep "^hi"
hi linux-dtb-legacy-rk3399 21.08.2 arm64 Linux DTB, version 4.4.213-rk3399
hi linux-headers-legacy-rk3399 21.08.2 arm64 Linux kernel headers for 4.4.213-rk3399 on arm64
hi linux-image-legacy-rk3399 21.08.2 arm64 Linux kernel, version 4.4.213-rk3399
hi linux-libc-dev:arm64 21.08.2 arm64 Armbian Linux support headers for userspace development
Feel free to ask if you want any more information!
