Dear Andi,
Apologies to reply in English, I can read German but not write it. We also use Mac as development platform. Here is our internal documentation about flashing images.
Upgrading to Buster
You might prefer to upgrade to Buster using apt. Unfortunately that breaks some of the Revolution Pi-specific programs, such as PiCtory. It would leave you unable to configure expansion modules. Kunbus provides an image for Buster that comes preconfigured to work well on the Revolution Pi. The preferred way to upgrade to Buster is to flash one of those onto the internal eMMC.
For the purpose of this tutorial, you will need a Revolution Pi that you'd like to upgrade to Buster, a development machine that you will use to commandeer the imaging process and a USB-A to micro-USB cable. The tutorial assumes you use some kind of UNIX derivative as your development machine, but the same process can be made to work under Windows.
Install Rpiboot
If you have not done so already, download and compile rpiboot on your development machine. The instructions can be found on the Raspberry Pi website.
https://www.raspberrypi.com/documentati ... odule.html
rpiboot makes the internal disk of the Revolution Pi available as a virtual disk on the development machine.
Download Buster Image
You can find the official Buster image on the downloads section of the Kunbus website.
https://revolutionpi.de/tutorials/downl ... evpiimages
The download consists of a ZIP file, which you can unpack to find documentation PDF's, a checksum file and the disk image itself as a .img file.
Flashing the eMMC
If this is not a factory fresh Revolution Pi, now is a good time to save the private key for Wireguard.
Power down the Revolution Pi.
On your development machine, start rpiboot.
$ cd rpiboot
$ sudo ./rpiboot
Waiting for BCM2835/6/7/2711...
This program will wait until it detects a booting Revolution Pi on a USB port.
Plug the Revolution Pi into the USB port of your development machine. Plug the USB cable into a USB-A port on your development machine and into the front micro USB port on the Revolution Pi, just under ethernet port A.
With the USB cable in place, power up the Revolution Pi. rpiboot will exit and you can see that the Revolution Pi's internal disk is now accessible as /dev/sda.
$ ls -l /dev/sd*
brw-rw---- 1 root disk 8, 0 Feb 12 21:28 /dev/sda
brw-rw---- 1 root disk 8, 1 Feb 12 21:28 /dev/sda1
brw-rw---- 1 root disk 8, 2 Feb 12 21:28 /dev/sda2
$ _
Next, flash the image onto the Revolution Pi using dd. Note that this command line assumes the GNU version of dd, which has nice features like progress reporting.
Writing an image of 4GB will take about 13 minutes, twice that when you make a backup of an 8GB Revolution Pi.
$ sudo dd bs=4M if=image-of-your-choice.img of=/dev/sda conv=fsync status=progress
You can reverse of= and if= to copy the internal eMMC of your Revolution Pi to a backup image file.
After flashing, remove the USB cable and reboot the Revolution Pi.
Post-Flash Password Configuration
Flashing a generic disk image onto a Revolution Pi does not give it the correct password and other configuration. The password on the sticker on the side of the housing is actually based on the MAC address of the Revolution Pi, plus its serial number.
Using SSH, login with pi / raspberry and follow instructions. Serial number is the middle of the three numbers on the front, bottom left, next to the QR code. Use MAC address of ethernet port A.
The default hostname is revpi. Depending on your wireless setup, you can log into it using the command below.
$ ssh
pi@revpi.local
pi@revpi.local's password: _
Type raspberry as password to start the configuration procedure. The Revolution Pi now prompts for its type, serial number and MAC address. With that information it will generate the passwords and resizes the internal eMMC disk to the size of the installed hardware.
Please enter the product (compact/connect/core/flat): connect
Please enter the serial number and MAC address on the front plate
of your RevPi to reset the image to factory defaults:
Serial: 40671
MAC Address: C83A-A791-8776
Password: 123aaa
Hostname: RevPi40671
MAC Address eth0: c85ea70287a6
MAC Address eth1: c85ea70287a7
Check that the password matches the one on the side of the housing. If it does not match, you can repeat the initialisation procedure to fix the error. Note that the hostname is now changed to RevPi<serial#>.
Hostname and First Post-Flash Upgrade
Each Revolution Pi is assigned a short, functional name to replace the generated hostnames. Since we have many, functional names help avoid making changes on the wrong system.
We follow the naming convention that seems to have grown in the Raspberry Pi community: a short, functional name followed by pi (e.g. raspi or revpi). Thus, we name ours roofpi for the one on the experimentation roof or boxpi for the one on the experimental container.
Pick a name and update /etc/hostname and /etc/hosts with the new name.
Next update all the packages to the latest version.
$ sudo vi /etc/hosts /etc/hostname
$ sudo apt update
$ sudo apt full-upgrade
$ sudo reboot
After rebooting, the system will come back under its new name, so you may have to adapt your previous SSH command.