Okay, I think I see the problem now. Your cmdline.txt is missing console=serial0,115200, which should stop agetty running on the UART. However, it is also missing console=tty1. The kernel is having to pick a console by itself, and it is choosing the UART after all.Here is my output from cat /proc/cmdline:
coherent_pool=1M 8250.nr_uarts=1 pci=pcie_bus_safe snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 smsc95xx.macaddr=D8:3A:DD:C8:AB:A7 vc_mem.mem_base=0x3fc00000 vc_mem.mem_size=0x40000000 root=PARTUUID=fafc7728-02 rootfstype=ext4 fsck.repair=yes rootwait quiet splash plymouth.ignore-serial-consoles cfg80211.ieee80211_regdom=GB
If you add console=tty1 back to cmdline.txt, that should inhibit the getty service and the port will remain in dialout group.
The default udev rules (present across most udev-based distros) already gave read-write access on all serial ports to group dialout. Your initial user is automatically a member of that group in Raspberry Pi OS.crw-rw---- 1 pi dialout 204, 74 Feb 5 10:17 /dev/ttyAMA10
The only reason I can see for changing the default ownership is if the dialout group is too coarse for you. Say you wanted to restrict multiple users each to their own specific ports by applying different rules to individual devices, instead of putting all the users in that one group.
Statistics: Posted by jojopi — Mon Feb 05, 2024 6:26 pm