Sorry for resurrecting this thread after quite some time. I have finally taken the crazy decision to port the entire Zynthian to postmarketOS for Pocophone F1(Crazy CPU power, lots of RAM, UFS storage 
).
While the road was bumpy so far, there is some progress, but am still seeking some help from the most experienced guys that worked on coding zynthian until now.
Thus, I’m just going to shoot the question straight away:
I can’t get how the setup script is calling the setup_first_boot script and then shutting down first time while the second time it should not.
More concise: The setup_system_rbpi_raspbian_lite_buster.sh is calling $ZYNTHIAN_SYS_DIR/scripts/set_first_boot.sh. There’s no guarding for this call. Next, at the end of set_first_boot.sh script, a poweroff command is issued. No flag checking or anything. So, theoretically, each time you would call this script, it will power off at that point, making the rest of the comands in setup_system_rbpi_raspbian_lite_buster.sh basically non-executable.
Am I missing something here?
LE: Should I create a separate topic specifically targeted for porting software to other platforms/OS-es? @jofemodo