Enabling Serial Console on MikroTik RouterOS x86

MikroTik RouterOS has piqued my interest lately, but before committing to buying some hardware I’d like to dabble. Fortunately MikroTik offers RouterOS x86, which allows you to install their OS on any x86 box. I have a PCEngines APU3 lying around which is the perfect little device for this. One problem though, the APU3 does not have a VGA out which is what RouterOS expects the user to use to install the OS.

However, there are a couple of ways we can get around this

Obtain Image

You can download RouterOS from MikroTik’s website here: https://mikrotik.com/download/routeros I chose the Long-Term x86 IMG Install Image, not the ISO.

Once it’s downloaded, you’ll need to unzip it, then open the image. This will depend on the OS you’re on — I’ve included instructions for macOS and Linux

macOS

-> hdiutil attach install-image-7.21.5.img
/dev/disk5          	                               	/Volumes/NO NAME
-> cd /Volumes/NO\ NAME
-> ls
1.npk        10.npk       12.npk       14.npk       15.npk       17.npk       2.npk        3.npk        4.npk
8.npk        9.npk        autorun.scr  CHOOSE       EFI          ldlinux.c32  ldlinux.sys  linux        syslinux.cfg

Linux

-> mkdir /mnt/routeros
-> sudo mount -o loop install-image-7.21.5.img /mnt/routeros
-> cd /mnt/routeros
-> ls
1.npk        10.npk       12.npk       14.npk       15.npk       17.npk       2.npk        3.npk        4.npk
8.npk        9.npk        autorun.scr  CHOOSE       EFI          ldlinux.c32  ldlinux.sys  linux        syslinux.cfg

Enable Serial Console

You’ll need to edit two lines to make serial console primary while also allowing VGA to continue working

• syslinux.cfg

LABEL system
  KERNEL linux
- APPEND load_ramdisk=1 -install -hdd
+ APPEND load_ramdisk=1 -install -hdd console=tty0 console=ttyS0,115200n8 earlyprintk=ttyS0,115200

• EFI/BOOT/refind.conf

menuentry "Install RouterOS" {
    loader /linux
-   options "load_ramdisk=1 root=/dev/ram0 -install -hdd"
+   options "load_ramdisk=1 root=/dev/ram0 -install -hdd console=tty0 console=ttyS0,115200n8 earlyprintk=ttyS0,115200"
}

Prepare Bootable USB

Once you’ve modified the files above, you can unmount/eject the disk. Then you’ll need to write it to a USB flash drive

sudo dd if=install-image-7.21.5.img of=/dev/disk7 bs=1M status=progress

Boot Installer

Once dd finishes in the previous step, you can take the flash drive and plug it into your device and boot from that USB. You should land on a screen like below

Booting from Hard Disk...

SYSLINUX 6.02 EDD 2013-10-13 Copyright (C) 1994-2013 H. Peter Anvin et al
Loading linux... o
Looking for harddrives......
                Welcome to MikroTik Router Software installation

Select 'Output Disk' using arrow keys. Press ENTER to confirm.

[X] I189971632(119 GB)           [ ] 4C530001251015101233(29 GB)*
Welcome to MikroTik Router Software hard disk installation 7.21.5
Press Ctrl-Alt-Delete to abort
                Welcome to MikroTik Router Software installation

Move around menu using 'p' and 'n' or arrow keys, select with 'spacebar'.
Select all with 'a', minimum with 'm'. Press 'i' to install locally or 'q' to
cancel and reboot.

  [X] system               [ ] gps                   [ ] tr069-client
  [ ] calea                [ ] iot                   [ ] ups
  [X] container            [ ] openflow              [X] wireless
  [X] dude                 [ ] rose-storage

dude (depends on system):
network monitoring and management


Reading: system-7.21.5....
Reading: wireless-7.21.5...
Reading: dude-7.21.5...
Reading: container-7.21.5...

Creating partitions...+(122070 MB)...

Formatting 'RouterOS' 100%ng 'RouterOS'
Formatting 'RouterOS Boot' 100%


readMBR: could not open /dev/mtdblock2: 2
open /dev/panics failed

Software installed.

Rebooting...

You can continue through the installer, then reboot when it’s complete.

Connecting via WinBox

The installer does not enable serial on the installation on your disk — you will be unable to see anything on serial after it boots the disk. Fortunately, using MikroTik’s WinBox, you can still gain access to the device. You can then use this access to enable serial permanently.

Open a terminal by clicking “New Terminal” on the left navigation. You can run the commands below to check the status of the console, set its speed, and enable it.

[admin@MikroTik] > /system/console print    
Flags: * - DEFAULT; X - DISABLED, F - FREE
Columns: PORT, VCNO, TERM
#    PORT     VCNO  TERM 
0 *X serial0        vt102
1 *F             1  linux
2 *F             2  linux
3 *F             3  linux
4 *F             4  linux
5 *F             5  linux
6 *F             6  linux
7 *F             7  linux
8 *F             8  linux
[admin@MikroTik] > port set serial0 baud-rate=115200 data-bits=8 parity=none stop-bits=1
[admin@MikroTik] > /system/console enable 0                                      
[admin@MikroTik] > /system/console print                                         
Flags: * - DEFAULT; F - FREE
Columns: PORT, VCNO, TERM
#    PORT     VCNO  TERM 
0 *F serial0        vt102
1 *F             1  linux
2 *F             2  linux
3 *F             3  linux
4 *F             4  linux
5 *F             5  linux
6 *F             6  linux
7 *F             7  linux
8 *F             8  linux

If you enable it, serial should start working right away. You may need to hit enter 1 or 2 times to get it to show up.

Alternative Method

If you don’t want to go through the hassle of modifying files, you can simply write the image to a USB drive, insert it into your device, then plug in a USB keyboard. When you boot it, it will go through the install process seen above — you’ll just need to do it blind and hit the necessary keys on your keyboard

For simplicity, you can just hit the following

1. Enter (to select the first drive)
2. i to install just system

If it finishes installing, it will reboot automatically. You can pick up from the WinBox step to connect to it and set up the serial console permanently.