Thanks @dtischler - I went through your explanation - sadly the paket with the tooling is not enough, the system just wants to flash the overall filesystem before it even dares to write some kB to the eeprom. In regards to the ARM leaflet I went ahead and did some small tutorial for with the 32.4.4 version, this is for the current Jetson Nano (4GB RAM, SD) and Jetson Nano (2GB RAM, SD) models, but I cannot test it on a ARM Mac, I would assume it needs at least some x86/x64 emulation, but never the less, all gals and guys with access to internet and an (even old) x86/x64 machine with current Ubuntu/Debian, this should help.
(This was tested on a headless Debian 10 machine and a 32 GB MicroSD Card was used - no warranty taken for any of this, it was just tested with a Jetson 4 GB and it is now working perfectly - but I cannot take any liability in any way )
0.) Power down your Jetson Nano
1.) Use a female/female jumper cable to cross the FC REC with one GND pin on the backside of the unit (close to the SD Card)
2.) Insert an empty, at least 16 GB big sd card
3.) On your recent (Ubuntu/Debian) Linux PC (could be that it needs to be x86/x64) prepare the overall system
sudo apt update
sudo apt install -y qemu-user-static
tar xf Tegra210_Linux_R32.4.4_aarch64.tbz2
sudo tar xpf ../../Tegra_Linux_Sample-Root-Filesystem_R32.4.4_aarch64.tbz2
4.) Power on the unit
5.) Connect it via Micro USB cable to the PC
6.) Flash the overall package
sudo ./flash.sh jetson-nano-qspi-sd mmcblk0p1
It took some time to get all data via USB 2.0 to the Jetson, but after the processed was finished in the flash tool, it rebooted the Jetson and started preparing Ubuntu. I let it run for some minutes before powering it down, removing the SD Card and the Jumper for the FC REC. I then put in a preconfigured balenaOS image sd card and saw it boot over the NVIDIA logo and successfully connect to balenaCloud.
Hope this helps future people until we get the issue resolved