Rock64 upgrade from 8.4.2 to 8.7.1 problem

Tried to update from 8.4.2 but it keeps saying

 APT upgrade
│  - Command: apt-get -y upgrade
│  - Exit code: 100
│  - DietPi version: v8.4.2 (MichaIng/master) | HW_MODEL: 43 | HW_ARCH: 3 |
│  - Image creator: DietPi Core Team
│  - Pre-image: Armbian
│  - Error log:
│ Reading package lists...
│ Building dependency tree...
│ Reading state information...
│ Calculating upgrade...
│ The following packages will be upgraded:
│   armbian-bsp-cli-rock64 armbian-firmware dirmngr dpkg gnupg gnupg-l10n
│   gnupg-utils gpg gpg-agent gpg-wks-client gpg-wks-server gpgconf gpgsm gpgv

E: Failed to fetch  404  Not Found [IP: 80]
E: Failed to fetch  404  Not Found [IP: 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

Please help!

Hmm looks like on apt package update you get redirected to an Armbian mirror that did not exist or has issues.

Could you try following

apt update
apt upgrade 

Here’s what it shows:

oot@DietPi:~# apt update
Hit:2 Index of /debian buster InRelease
Hit:3 Index of /debian buster-updates InRelease
Ign:1 Index of /apt/ buster InRelease
Hit:5 Index of /debian-security buster/updates InRelease
Err:4 Index of /apt/ buster Release
404 Not Found [IP: 80]
Hit:6 Index of /debian buster-backports InRelease
Reading package lists… Done
E: The repository ‘ buster Release’ no longer has a Release file.
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
root@DietPi:~# apt upgrade
E: dpkg was interrupted, you must manually run ‘dpkg --configure -a’ to correct the problem.

I did

dpkg --configure -a

Then apt update & apt upgrade
then dietpi-update and it works this time.

For anyone who has similar problems.