I have customized a headless raspberry pi OS (Dec 2020 version). I performed all customizations while running the OS from a microSD card.
As a last step , I
dd the microSD to a USB drive. The system boots and works fine apart from one detail. While from the microSD card I often used the serial to see boot messages and get a login prompt. Now that I boot from USB I can still see the boot messages on serial, but I get no login prompt.
The serial device that shows up in raspberry pi's gpio pins is
Needless to say
cmdline.txt boot files are the same in microSD card and USB drive.
console=serial0,115200 console=ttyS0,115200 console=tty1 root=PARTUUID=d8b18b6e-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait splash plymouth.ignore-serial-consoles
$ cat /boot/config.txt | egrep -v '^(#|$)' dtparam=audio=on [pi4] dtoverlay=vc4-fkms-v3d max_framebuffers=2 [all] enable_uart=1
I can only see a email@example.com in systemd - which takes care of a login prompt for when connecting a screen. But I would still get a login from the serial gpio pins. Do you have any idea what is missing to get login prompt in serial while booting from USB?