I have flashed debian stretch OS on my SD card (/dev/mmcblk0) and BalenaOS v2.41 on my emmc (/dev/mmcblk2). I use a custom board based on Humming board.
Before first connection of BalenaOS, I have a configuration stage to register device on BalenaCloud, generate config.json and mount it on boot partition of BalenaOS and others configurations point.
One of point needs to modify configuration file in /etc/ of BalenaOS. When I mount rootfs of Balena OS (/dev/mmcblk 2p1) I don’t find any file on /etc directory.
Other approach I tried, is to use chroot to switch filesystem to use BalenaOS executables. Nonetheless chroot command need /bin/sh of BalenaOS as entrypoint. But on BalenaOS rootfs (/dev/mmcblk2p1) I don’t have any /bin/ directory.