On Nov 24/20, a new version of the Turtlebot3 aManual was announced, that is an excellent resource for both ROS & ROS2. The 3.2 SBC Setup states its specifically for Raspberry Pi 3B+ using the Ubuntu 20.04.1 Preinstalled Server. (for RasPi). So my question is, that since an image for Raspberry Pi 4 64-bit is available (https://ubuntu.com/download/raspberry-pi), can you confirm that the eManual procedure following Ubuntu 20.04 installation steps in 3.2. Step 3.2.5 to install ROS Foxy will work? Can you give an ETA for a new updated eManual?
You can apply the eManual instructions for Raspberry Pi 4 with the correct Ubuntu image for your RPi 4.
When I tested with my RPi4 2GB, the installation process wasn’t much different from that of RPi 3B+.
RPi 4 instruction will be officially available by the second quarter of 2021 at the latest.