OpenWRT - RB750GL / RB750 - UniFi Ready

RB750GL (both Vlan.500 + Vlan.600 working)  /  RB750 (Vlan.500 working)

( Jun'2017 update : refer to LEDE 17.01.1 on RB750GL/RB750 )

I have not been using MirkoTik for quite some time, also getting tire on it's QoS ...
So recently pulled out the RB750GL & RB750, hoping to run the easier OpenWRT QoS ...

Important note : I'm on one-way-ticket and ready to brick my toys without any intention to return to stock firmware (since I have extra toys).  If you wish to return to stock firmware later, please go Googling research on how to backup/restore the orginal firmware/key first before start the journey.


Basicallly I followed :

Guide & reference (thanks & credits to the respective author smile :
Current OpenWRT stable release (CC 15.05.1) :

My setup :


The initial VM to boot OpenWRT on RAM is not available on 15.05.1,
use 14.07 instead.

Copy to folder:

openwrt-15.05.1-ar71xx-mikrotik-DefaultNoWifi-rootfs.tar.gzRename to :
Copy to folder:
openwrt-15.05.1-ar71xx-mikrotik-vmlinux-lzma.elfRename to :
Copy to folder:


  • On my Win10 laptop get ready the PuTTY & WinSCP
  • 2 Cat5e LAN cables
  • .

Flashing steps

Find out my ASUS U32U LANport Ethernet name, open Terminal and type:  ifconfig
(mine is named "enp4s0f2", write down yours and change the following command entries accordingly)

  • Unplug ALL cables from RB750GL
  • Connect LAN cable from U32U to RB750GL Port1, then type :

sudo ip a a dev enp4s0f2

sudo dnsmasq --no-daemon --port=0 --dhcp-range=",,12h" --enable-tftp --bootp-dynamic --dhcp-boot="openwrt-ar71xx-mikrotik-vmlinux-initramfs.elf" --tftp-root="/home/u32u/Downloads/Flash"

  • Back to RB750GL, press and continue holding the Reset button, then insert power cable
  • Keep holding the Reset button, only release until the U32U assigned IP to the RB750GL (when message show "dnsmsq-dhcp: BOOTP ...")

Wait patiently until the VM is loaded to the RB750GL RAM, once it's rebooted into OpenWRT, can terminate the process and unplug LAN cable from Port1 (when message show "dnsmasq-dhcp: DHCPDISCOVER ...)

Next is to serve and write OpenWRT directly to the device permanently.
Connect LAN cable from U32U to RB750GL any port EXCEPT Port1 (I use Port3
), then type :

sudo ip a a dev enp4s0f2

cd /home/u32u/Downloads/Flash2

python3 -m http.server 8080

  • Back to my Win10 laptop, connect LAN cable to RB750GL any port EXCEPT Port1 (I use Port2)
  • Launch PuTTY, login to as root (no password needed), then type:


Noticed it will load both kernel & rootfs from the http server ...  

... as shown on my U32U ...  

On PuTTY, when the message show "Image written ...", then can type :

reboot && exit

The device will reboot again, wait patiently until it's fully booted completely, it can take a while.

That's it, OpenWRT CC15.05.1 has been installed on RB750GL laughing

Switch Vlans config for UniFi Vlan.500 (Internet PPPoE) and Vlan.600 (IPTV) 

Can also use WinSCP to setup UniFi as follows ( /etc/config/network ) :

The above flashing process also works on RB750

Only manage to create a Vlan.500 for UniFi, still no luck to get 2nd Vlan.600 on this switch chip ...

I wanted to flash LEDE (current stable 17.01.0) since I prefer the CAKE QoS (piece_of_cake script) which I have used it on DIR-885L :

But somehow can't make the LEDE works, it keep endless reboot after writing the kernel & rootfs undecided

Somehow LEDE seem to have different flash layout on RB750GL/RB750.
This is OpenWRT layout (on Trunk), notice it's using "rootfs" :

This is LEDE 17.01.0 layout, notice it's using "ubi" :

Not sure whether the new Ubi layout causes the endless boot issue or not innocent ...

Jun'2017 update : Finally, LEDE 17.01.1 on RB750GL/RB750 laughing