MikroTik RouterBoard RB433 / RB433AH / RB433UAH

The Routerboard RB433UL is currently not supported. This Board was initally based upon Atheros AR7161 400MHz CPU but now it is based upon Atheros AR7130 300Mhz CPU. RB433UL has 64MB RAM and the serial console is not supported by uboot.

Remark: There are two Resets: Reset 1 (Button) and Reset 2 (Pad).

  • Reset 1 is to reset the RouterOS and for force the netinstall (PXE).
  • Reset 2 is to choice the backup uboot.

Sometimes you must press both.

:!: Please have a look at Common Procedures for Mikrotik RouterBoard Products for installation instructions and other information.

The content of this page here is partially deprecated !

Common Procedures for Mikrotik RouterBoard Products

Here are the three main steps of the installation:

  • Boot the board on OpenWrt from the network (netboot): DHCP and TFTP servers required on the host.
  • Install OpenWrt to the internal flash with wget2nand: HTTP or FTP server required on the host. ( wget2nand is no longer used! )
  • get the sysupgrade-image and install it via sysupgrade in the webif or via shell
  • Reboot on the new installation, configure, etc.

The bootloader of RB433 is able to load an image in elf format via BOOTP into RAM and execute it.

Download the Image

If you are not comfortable with building your own trunk you can get the image from official OpenWRT download servers as of 14.07 release:


:!: (At least for RB411AH) The most recent images are to big to load via bootp.

So this image does not work: http://downloads.openwrt.org/releases/19.07.4/targets/ar71xx/mikrotik/openwrt-19.07.4-ar71xx-mikrotik-vmlinux-initramfs.elf

You would get a error like "kernel out of range".

But the 17.01.07 image did work:

Build the Target

You need to get OpenWrt trunk. In menuconfig choose:

  • Target System: Atheros AR7xxx/AR9xxx
  • Subtarget: Devices with NAND flash (mostly Mikrotik)
  • Target Images: ramdisk (and also tar.gz if you plan to do a permanent install with the same image)

Now build the ram disk version. While it's building create the tftp-root directory if not already done and a symlink to the ram disk image

sudo mkdir -p /tftpboot
sudo ln -sf $(HOME)/openwrt/rb433uah-netboot/bin/ar71xx/openwrt-ar71xx-nand-vmlinux-initramfs.elf /tftpboot/openwrt.elf

Setup the Host

You need a BOOTP and a TFTP server on your host machine, we use dnsmasq here, since it can provide both services. Install dnsmasq with:

sudo apt-get install dnsmasq

Changes in /etc/dnsmasq.conf:

  • only listen on the interface which is directly connected to the RouterBoards WAN (PoE) port. e.g.
  • allow a DHCP range, e.g.
  • allocate an IP address to the board, e.g.

    (replace the XX with the MAC address of your board!)

  • enable dnsmasq's built-in TFTP server
  • set the root directory for files available via FTP.
  • set filename (produced above) and tftpd server for BOOTP, e. g.

Finally restart dnsmasq

sudo /etc/init.d/dnsmasq restart

You will probably need to set the IP of the interface manually:

sudo ip addr add dev eth0

Setup the Target

  • Connect to the serial port with a null modem cable (115200, 8N1).
  • Press a key shortly after powering the board.
  • Press o to change the boot device
  • Press e to boot from ethernet in the future.
  • Press x to leave setup (-o-e-x is needed only once, the boot method is saved in non-volatile memory)

If everything is setup correctly it should look like:

RouterBOOT booter 2.16

RouterBoard 433AH

CPU frequency: 680 MHz
  Memory size: 128 MB

Press any key within 2 seconds to enter setup..
trying bootp protocol.......... OK
Got IP address:
resolved mac address 4E:80:00:00:00:00
transfer started ................................... transfer ok, time=7.16s
setting up elf image... OK
jumping to kernel code
Linux version (joerga@thinkpad) (gcc version 4.1.2) #2 Mon Nov 10 11:23:37 CET 2008
console [early0] enabled

You need a working netboot first, see above. Please note also that you cannot reflash from a previous OpenWrt installation, you need the netboot in any case.

Target Image

If you want to use the same trunk image as the netboot image (cf. above), you need to have the tar.gz target selected in the Target Images menu and rebuild if you didn't select it before. You can also use one of the pre-built images (tested with 12.09-rc2); in the download area, browse the ar71xx/nand/ directory and pick the two following files:

  • openwrt-ar71xx-nand-rootfs.tar.gz
  • openwrt-ar71xx-nand-vmlinux-lzma.elf

Update: For 14.07 release images are provided at


If you don't have many devices to install and your netbooted system can access the Internet, you can probably pass the download URL directly to wget2nand as well, that will save you the web server configuration step (see below).

Save your RouterOS license key

If you have access to the MikroTik's Winbox software, you can export the license file from System→Licence, as stated on the RouterBoard 411 page.

Otherwise, boot RouterOS and export the key to a file:

/system license output

Then list the files on your device to see which file the .key file was saved:

/file print

On a fresh install, the key file should be #1 (or #0 on a RB433UAH); to open the editor with file #1, type:

/file edit 1 value-name=contents

Then copy-paste the text in a file on your computer. The differences between the obtained key file and a key exported with Winbox are that the SoftwareID line is not present in the latter, and there are no empty lines, so you should probably delete all the empty lines in your file prior to import it for a new installation; the SoftwareID line should not bother the installer (untested).

Erase the NAND Flash

If you want to install OpenWrt permanently into the NAND flash you once need to erase the NAND flash to get rid of the RouterOS stuff:

  • connect via serial line
  • press a key shortly after powering the RB433 up
  • press e and type yes to format the flash from the bootloader

Setup the Host

An HTTP web server is required on the host, e.g. mini-httpd in Ubuntu. Install the mini-httpd web server

sudo apt-get install mini-httpd

In /etc/default/mini-httpd change

  • Start daemon

In /etc/mini-httpd.conf change

  • On which host mini_httpd should bind
  • Run in chroot mode
  • Where are the web files stored

Restart the mini-httpd web server

sudo /etc/init.d/mini-httpd restart

Install OpenWrt into Flash

  • Start netboot (see above).
  • Press ENTER to get a shell prompt.
  • Execute:

This script will set an IP address via dhcp on br-lan. The output should look like:

root@OpenWrt:/# wget2nand
Connecting to (
kernel               100% |*******************************|  1041k  0:00:00 ETA
Connecting to (
rootfs.tgz           100% |*******************************|  4243k  0:00:00 ETA
Erasing filesystem...
[  137.110000] nand_erase_nand: attempt to erase a bad block at page 0x00002240
[  137.140000] nand_erase_nand: attempt to erase a bad block at page 0x00003ac0
[  137.180000] nand_erase_nand: attempt to erase a bad block at page 0x00005d40
[  137.620000] nand_erase_nand: attempt to erase a bad block at page 0x00026a80
[  137.850000] nand_erase_nand: attempt to erase a bad block at page 0x000373c0
[  137.860000] nand_erase_nand: attempt to erase a bad block at page 0x00037440
[  138.000000] yaffs: dev is 32505861 name is "mtdblock5" rw
[  138.000000] yaffs: passed flags ""
[  138.020000] yaffs: dev is 32505862 name is "mtdblock6" rw
[  138.020000] yaffs: passed flags ""
Mounting /dev/mtdblock6 as new root and /dev/mtdblock5 as kernel partition
Copying kernel...
Preparing filesystem...
Cleaning up...
Image written, you can now reboot.  Remember to change the boot source to Boot from Nand
  • Reboot the RB433 and change the boot source to NAND.

The MicroSD Slot needs SPI-Bus sharing support, which is not implemented in Backfire.

SPI-Bus sharing has been implemented in Trunk r22862 the MicroSD Slot is usable now. Read speed ist about 0.92 MB/s (11/13/10: I get I/O and -89 errors on the SPI bus while assessing the microSD card).

To have the USB ports work on the RB433UAH, you need to install the kmod-usb2 package, as explained on the USB Basic Support page. See also the USB Overview page.

The ethernet jacks are mapped to port numbers of the IP175C switch (looking at the front of the board):

[ port 4 (PoE)] ( serial ) [port 1] [port 2]
Interface Switch port
eth0 4
eth1 1 & 2

Port 1 and port 2 are switched in the default config.

This website uses cookies. By using the website, you agree with storing cookies on your computer. Also you acknowledge that you have read and understand our Privacy Policy. If you do not agree leave the website.More information about cookies
  • Last modified: 2024/02/12 08:58
  • by