TFTP to Flash Ubiquiti UniFi nanoHD

I’ve spent about 14 hours on this today trying to accomplish this in ArchLinux (EndeavourOS). It hasn’t been entirely bashing my head into failed commands and errors. A good part of the “pre-game” was soldering a USB to serial cable to the AP’s J2 port that had no preinstalled header… and I basically had a curling iron and a blow dryer to get the harvesting of donor header parts and installation to the AP’s board… fun lol!

ANYWHO, EOS does not come with TFTP installed. So I installed it (I think with yay but I REALLY don’t remember; it’s been a long day; this one: TFTP - ArchWiki ). The instructions to initiate the flashing process of the AP via tftp is explained on Ubiquiti’s site (here: ). The problem is when I try to “put” the file, I either get a “No such file or directory” error or a “Transfer timed out.” error.

I CANNOT for the life of me understand how to properly get the image file transferred to the AP via TFTP. There seems to be some kind of permissions or settings or something I’m missing. I’ve n00b-faced it as far as I can and am just stumped. What am I missing? (Thanks all in advance!)

You had me at the Curling Iron part :wink:

I wish I could help you with the rest of this but I’m sure there will be somebody around that can give you some guidance…

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@GUIn000b I to think what you are trying to do is very interesting. I have unifi equipment and have a little experience with there operating system. But I am confused what you are trying to do with your AP. It sound like you are trying to add some software directly to the AP completly bypassing its controller is that correct?

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First, make sure the TFTP server is working. From another system install the tftp client program and make sure you can tftp to your server and “get” the file. Something like:

tftp -v -m binary -c get filename

If that works… great! If not, there could be a dozen reasons.

Does netstat -lu show “” or similar?
Does firewall-cmd --list-all show “69/udp” or “tftp”?
Does it work after setenforce 0 or chmod -R 755 /tftpboot?

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I want to install OpenWRT as the OS on the AP. In order to do that, I have to downgrade its firmware to 3.9.27 to facilitate the OpenWRT flashing procedure. I have a Ubiquiti EdgeRouter 4 that I’ve already flashed to OpenWRT. I love it!

I can bring this thread to a close now, though. I broke down and switched over to a windows machine to attempt this. (I’m a new migrant from the M$ plantation to Planet Linux lol). I had 2 major problems going on.

  1. I connected the RX wire of my UART cable to the RX pin of the J2 header, and likewise the TX wire to the TX pin. NO WONDER I wasn’t getting anything from the console lol!

  2. Once I was able to see console output, I then learned my previous attempts to put the device into TFTP mode were actually insufficient. By being able to observe the console output, I was able to see just exactly how long I needed to hold that pesky reset button. Once I ACTUALLY got it into auto-TFTP mode, everything was smooth sailing with Pumpkin and Putty.

Now I just have to use the console to facilitate copying openwrt over and installing it and I should be good to go. I’m guessing I need to use the console connection to enable SSH, then I can SCP the openwrt file over. Anyway, thanks all for the input! :slight_smile:


Yes you will need to use the console connection enable an ssh connection to the AP.

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Wrapping up, I just wanted to say thanks again to all, and officially my AP is up and running OpenWRT. After flashing to the 3.9.27 Ubiquiti firmware, I dumped the OpenWRT firmware onto a local WebDAV share so that I could just wget it over http (https wget would have required installing SSL packages and things to the AP first lol! I didn’t want to risk messing up the progress, so I made it work as-is).

This was definitely strenuous, tenuous and just an all around long-winded adventure. … On to the next! :wink:

Tell us more about it. What do you like about OpenWRT? Why would you prefer it over Vyatta+Debian based EdgeOS?

I’ve been running EdgeRouter X for close to seven years. Was thinking of switching to OpenWRT if UI abandoned EdgeMax series.

I really like the idea that a single text-based configuration file rules all in Vyatta/EdgeOS.


I’ve never heard of Vyatta so I won’t be able to give you a comparison. My main goal is to go open source as much as possible. The cost of proprietary solutions has gotten too high in more ways than one for my comfort. This Edge Router and UAP are also my last purchases of Ubiquiti equipment. They make good equipment and I’d probably still recommend them to SMB’s that have a budget to pay for it. This is mostly my home setup to start with mostly because I want all of those robust features, but the long term goal is to develop my working knowledge of open source solutions to the masterful extent that I have with M$/Ubiquiti/others. I know I’m late to the party, but better late than never! :wink:


It is never to late to learn something new. Look at me I am almost 60 years old, and I am trying to switch carriers, studying, and trying to find a job as an Network engineer. I have heard good things about OpenWRT, and right now if I was not trying to familiarize myself with Cisco systems I would be messing with OpenWRT.