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Mikrotik RouterBoard RB133

The device is supported in OpenWrt since Kamikaze.

Hardware info

Architecture: MIPS
Vendor: MikroTik, ADMtek (Infineon)
Bootloader: RouterBOOT
System-On-Chip: ADM5120 (Little Endian)
CPU Speed: 175 Mhz
Flash size: 64/128 MiB
Wireless: 3x Type III miniPCI slot
Ethernet: 3 x 10/100 Base-TX Ethernet Ports (with Auto MDI/MDIX)
USB: no
Serial: yes
JTAG: no?


This article will be completed soon, see oldwiki now.

:!: If you flash OpenWrt from NetBoot facility, you will lose your RouterOS licence.

The installation of OpenWrt on this board is only possible by using the NetBoot facility - you will boot into the RAMdisk version of OpenWrt and use it to flash the permanent OpenWrt image into NAND. You will need:

  1. A serial port (or a USB-RS232 serial converter) and a null modem cable as console (standard serial cable wont work).
  2. An ethernet port and cable to download the NetBoot kernel and the NAND image.
  3. A DHCP server to tell the RB1xx where to get it's netboot image (e.g. DnsMasq).
  4. A TFTPD server to supply the NetBoot image to load a barebone OpenWrt RAMdisk image (e.g. DnsMasq).
  5. A web server to serve up the permanent version of the OpenWrt kernel and rootfs (you can use SCP as well).

Connect your RouterBoard using both ethernet and null modem cable to a PC.

Building images

See official howto for more info.

:!: If you select the squashfs image, it may take quite a few minutes for the device to power on.

You will have to run the building process twice, because you will need both RAMdisk image and stock OpenWrt kernel+rootfs.

Build profile should be:

  • Target System:
  • Target Profile:

To install openwrt on mikrotik rb133c a serial null modem cable is required on the local machine , an Ethernet cable , in addition to the proper functioning of a tftp and dhcp server on the local machine .

If the rb133c has already mounted openwrt you can directly go to the “ Writing nand ”

booting from ethernet

Once you have connected the serial cable and ethernet between rb133c and the local PC and you enable the tftp and dhcp server , copy the vmlinux file in the appropriate TFTP server root and start the serial console .

  minicom -d / dev / ttyUSB0 115200

then access to the serial console terminal , connect the rb133c power and press any key to blocccare the boot sequence .

RouterBOOT booter 2:18 RouterBoard 133C CPU frequency : 175 MHz Memory size: 16 MB

Press any key within 2 seconds to enter setup. … your choice: e - format nand Do you realy want to format your nand? that would result in losing all your data type "yes" to confirm: yes formatting nand… done! … your choice: p - boot protocol Choose which boot protocol to use:

 1 - bootp protocol
 2 - dhcp protocol

your choice: 2 - dhcp protocol … your choice: o - boot device Select boot device:

 e - boot over Ethernet
 n - boot from NAND, if fail then Ethernet
 1 - boot Ethernet once, then NAND
 o - boot from NAND only
 b - boot chosen device

your choice: n - boot from NAND, if fail then Ethernet … your choice: x - exit setup … trying dhcp protocol…. OK resolved mac address 00:26:B9:03:BC:3B Gateway: transfer started ………………………… transfer ok, time=2.47s setting up elf image… OK …

Writing nand

If you already have in rb133c openwrt you can upgrade the firmware via ssh , or even by serial console .

root@OpenWrt:/# mkdir /mnt/kernel ; mount /dev/mtdblock2 /mnt/kernel
yaffs: dev is 32505858 name is "mtdblock2"
yaffs: passed flags ""
yaffs: Attempting MTD mount on 31.2, "mtdblock2"
root@OpenWrt:/# mkdir /mnt/rootfs ; mount /dev/mtdblock3 /mnt/rootfs
yaffs: dev is 32505859 name is "mtdblock3"
yaffs: passed flags ""
yaffs: Attempting MTD mount on 31.3, "mtdblock3"
root@OpenWrt:/# passwd
Changing password for root
New password:
Retype password:
Password for root changed by root

Now back to your local machine , disable the DHCP server , then :

sudo ifconfig eth0 netmask up
scp openwrt-adm5120-rb1xx-vmlinux.elf root@
scp openwrt-adm5120-rb1xx-rootfs.tar.gz root@

Then return in the serial console to decompress the rootfs and restart the rb133c .

root@OpenWrt:/# cd /mnt/rootfs/
root@OpenWrt:/mnt/rootfs# gunzip openwrt-adm5120-rb1xx-rootfs.tar.gz
root@OpenWrt:/mnt/rootfs# tar xf openwrt-adm5120-rb1xx-rootfs.tar 
root@OpenWrt:/mnt/rootfs# rm openwrt-adm5120-rb1xx-rootfs.tar
root@OpenWrt:~# reboot

At this point the rb133c should listen to telnet to .

Linux howto

Windows howto

:!: Disable ANY firewall on your PC.

  1. Download Putty, run it, select Connection type: Serial, Serial line: COMx (x = number, depends on your configuration), Speed: 115200, and Open.


Atheros-based card are supported. The device doesn't work with Broadcom cards, since kmod-ssb causes kernel panic at startup.

Useful sources

This page has been assebled from a number of different pages from the oldwiki and current wiki. See them for more (possibily outdated) informations.


toh/mikrotik/rb133.txt · Last modified: 2018/02/18 20:40 by tmomas