HOW TO - Connect the serial console

[markb1]

So by adding this line to /boot/armbianEnv.txt, I get a lot more output after the "bootconsole" message:

Code:

console=serial

The console variable appears to default to "both" in boot.cmd. So that option doesn't seem to work correctly.

Here's the output I now get:

Code:

4239367 bytes read in 490 ms (8.3 MiB/s) 18667528 bytes read in 2010 ms (8.9 MiB/s) 87955 bytes read in 142 ms (604.5 KiB/s) ** File not found /boot/dtb/rockchip/overlay/rockchip-fixup.scr ** ## Loading init Ramdisk from Legacy Image at 04000000 ...   Image Name:   uInitrd   Image Type:   AArch64 Linux RAMDisk Image (gzip compressed)   Data Size:    4239303 Bytes = 4 MiB   Load Address: 00000000   Entry Point:  00000000   Verifying Checksum ... OK ## Flattened Device Tree blob at 01f00000   Booting using the fdt blob at 0x1f00000   Loading Ramdisk to f5af8000, end f5f02fc7 ... OK   reserving fdt memory region: addr=1f00000 size=7b000   Loading Device Tree to 00000000f5a7a000, end 00000000f5af7fff ... OK Starting kernel ... [    0.000000] Booting Linux on physical CPU 0x0 [    0.000000] Initializing cgroup subsys cpuset [    0.000000] Initializing cgroup subsys cpu [    0.000000] Initializing cgroup subsys cpuacct [    0.000000] Linux version 4.4.174-rockchip64 (root@armbian.com) (gcc version 7.2.1 20171011 (Linaro GCC 7.2-2017.11) ) #6 SMP Sun Feb 10 10:43:16 CET 2019 [    0.000000] Boot CPU: AArch64 Processor [410fd034] [    0.000000] earlycon: Early serial console at MMIO32 0xff1a0000 (options '') [    0.000000] bootconsole [uart0] enabled Loading, please wait... starting version 232 Begin: Loading essential drivers ... done. Begin: Running /scripts/init-premount ... done. Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done. Begin: Running /scripts/local-premount ... Scanning for Btrfs filesystems done. Begin: Will now check root file system ... fsck from util-linux 2.29.2 [/sbin/fsck.ext4 (1) -- /dev/mmcblk0p1] fsck.ext4 -a -C0 /dev/mmcblk0p1 /dev/mmcblk0p1: Superblock last mount time (Thu Nov  3 17:16:42 2016,        now = Fri Jan 18 08:50:09 2013) is in the future. FIXED. /dev/mmcblk0p1: Superblock last write time is in the future.        (by less than a day, probably due to the hardware clock being incorrectly set) /dev/mmcblk0p1: 36772/960992 files (0.2% non-contiguous), 354106/3843376 blocks done. done. Begin: Running /scripts/local-bottom ... done. Begin: Running /scripts/init-bottom ... done. Welcome to Debian GNU/Linux 9 (stretch)! [  OK  ] Listening on Syslog Socket. [  OK  ] Started Dispatch Password Requests to Console Directory Watch. [  OK  ] Listening on fsck to fsckd communication Socket. [  OK  ] Reached target Remote File Systems. [  OK  ] Listening on udev Kernel Socket. [  OK  ] Reached target Swap. [  OK  ] Created slice System Slice.         Mounting Debug File System... [  OK  ] Listening on udev Control Socket.         Mounting POSIX Message Queue File System... [  OK  ] Listening on Journal Socket (/dev/log). [  OK  ] Created slice system-getty.slice. [  OK  ] Set up automount Arbitrary Executab…rmats File System Automount Point. [  OK  ] Created slice User and Session Slice. [  OK  ] Listening on Journal Audit Socket. [  OK  ] Started Forward Password Requests to Wall Directory Watch. [  OK  ] Reached target Paths. [  OK  ] Reached target Encrypted Volumes. [  OK  ] Listening on /dev/initctl Compatibility Named Pipe. [  OK  ] Created slice system-serial\x2dgetty.slice. [  OK  ] Listening on Journal Socket.         Starting Journal Service...         Starting Restore / save the current clock...         Starting Create list of required st…ce nodes for the current kernel...         Starting Load Kernel Modules...         Starting Nameserver information manager...         Starting Set the console keyboard layout... [  OK  ] Reached target Slices.         Starting Remount Root and Kernel File Systems...         Mounting Huge Pages File System... [  OK  ] Mounted POSIX Message Queue File System. [  OK  ] Mounted Debug File System. [  OK  ] Mounted Huge Pages File System. [  OK  ] Started Restore / save the current clock. [  OK  ] Started Create list of required sta…vice nodes for the current kernel. [  OK  ] Started Load Kernel Modules. [  OK  ] Started Remount Root and Kernel File Systems. [  OK  ] Started Nameserver information manager.         Starting Load/Save Random Seed...         Starting udev Coldplug all Devices...         Starting Apply Kernel Variables...         Mounting Configuration File System...         Mounting FUSE Control File System...         Starting Create Static Device Nodes in /dev... [  OK  ] Mounted Configuration File System. [  OK  ] Mounted FUSE Control File System. [  OK  ] Started Journal Service. [  OK  ] Started Set the console keyboard layout. [  OK  ] Started Load/Save Random Seed. [  OK  ] Started Apply Kernel Variables. [  OK  ] Started Create Static Device Nodes in /dev.         Starting udev Kernel Device Manager... [  OK  ] Reached target Local File Systems (Pre).         Mounting /tmp...         Starting Flush Journal to Persistent Storage... [  OK  ] Mounted /tmp. [  OK  ] Reached target Local File Systems.         Starting Armbian ZRAM config...         Starting Raise network interfaces...         Starting Set console font and keymap... [  OK  ] Started udev Kernel Device Manager. [  OK  ] Started udev Coldplug all Devices. [  OK  ] Started Set console font and keymap. [  OK  ] Started Flush Journal to Persistent Storage.         Starting Create Volatile Files and Directories... [  OK  ] Started Create Volatile Files and Directories. [  OK  ] Reached target Sound Card. [  OK  ] Started Entropy daemon using the HAVEGE algorithm. [  OK  ] Reached target System Time Synchronized.         Starting Update UTMP about System Boot/Shutdown... [  OK  ] Found device /dev/ttyS2. [  OK  ] Started Update UTMP about System Boot/Shutdown. [  OK  ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch.         Starting Load/Save RF Kill Switch Status... [  OK  ] Started Load/Save RF Kill Switch Status. [  OK  ] Started Raise network interfaces. [  OK  ] Started Armbian ZRAM config.         Starting Armbian memory supported logging... [  OK  ] Started Armbian memory supported logging. [  OK  ] Reached target System Initialization.         Starting Armbian hardware optimization... [  OK  ] Started Daily Cleanup of Temporary Directories. [  OK  ] Started Daily apt download activities. [  OK  ] Started Daily apt upgrade and clean activities. [  OK  ] Reached target Timers.         Starting Armbian hardware monitoring... [  OK  ] Listening on D-Bus System Message Bus Socket. [  OK  ] Reached target Sockets. [  OK  ] Started Armbian hardware optimization. [  OK  ] Started Armbian hardware monitoring. [  OK  ] Reached target Basic System.         Starting LSB: Start/stop sysstat's sadc...         Starting LSB: Load kernel modules needed to enable cpufreq scaling...         Starting Login Service...         Starting System Logging Service... [  OK  ] Started D-Bus System Message Bus.         Starting Save/Restore Sound Card State...         Starting Network Manager... [  OK  ] Started Regular background program processing daemon. [  OK  ] Started System Logging Service. [  OK  ] Started Save/Restore Sound Card State. [  OK  ] Started LSB: Start/stop sysstat's sadc. [  OK  ] Started Login Service. [  OK  ] Started LSB: Load kernel modules needed to enable cpufreq scaling.         Starting LSB: set CPUFreq kernel parameters... [  OK  ] Started LSB: set CPUFreq kernel parameters.         Starting LSB: Set sysfs variables from /etc/sysfs.conf... [  OK  ] Started LSB: Set sysfs variables from /etc/sysfs.conf. [  OK  ] Started Network Manager.         Starting Network Manager Wait Online... [  OK  ] Reached target Network.         Starting OpenBSD Secure Shell server... [  OK  ] Started Unattended Upgrades Shutdown.         Starting Permit User Sessions... [  OK  ] Started Permit User Sessions.         Starting Network Manager Script Dispatcher Service... [  OK  ] Started Network Manager Script Dispatcher Service.         Starting Hostname Service... [  OK  ] Started OpenBSD Secure Shell server. [  OK  ] Started Hostname Service.         Starting Authorization Manager... [  OK  ] Started Authorization Manager. [  OK  ] Started Network Manager Wait Online. [  OK  ] Reached target Network is Online.         Starting LSB: Advanced IEEE 802.11 management daemon...         Starting /etc/rc.local Compatibility...         Starting LSB: Start NTP daemon... [  OK  ] Started LSB: Advanced IEEE 802.11 management daemon. [  OK  ] Started /etc/rc.local Compatibility. [  OK  ] Started Getty on tty1. [  OK  ] Started Serial Getty on ttyS2. [  OK  ] Reached target Login Prompts. [  OK  ] Started LSB: Start NTP daemon. [  OK  ] Reached target Multi-User System. [  OK  ] Reached target Graphical Interface.         Starting Update UTMP about System Runlevel Changes... [  OK  ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 rockpro64 ttyS2 rockpro64 login:

I'm still getting a bunch of junk at the very beginning (not shown), probably due to mismatched baud rate. I still haven't found a way to set the baud rate for the very early boot stages. Perhaps it's impossible to change. And there's still that weird "bootconsole [uart0] enabled" message, which appears to be pointing to the wrong port.