Fritzbox 3370 Flashing (Hynix)

So Karl over at TRC got one of thes in for us to look at using with customised OpenWRT/LEDE firmware for a large project rolloput. On paper they are perfect and have all we need. Ok we cant use the DECT radio but hey.

SO a quick look over at and this should be easy. Got the UART header soldered in, I have the bnoot process stopped and ready to go….


As is usually the case with OSS the documentation is a little poor. Starting with the fact that the supplied Image on the page is one file, and then the instructions go on about needing to upload two.

More searching just initally found more complaints of the same 🙁

I did eventually find Micheal Kuron’s blog at which then gave a better link for formwares. the are snapshots so up to date too. The link for these is

Make sure you get the right one. As detailed on the OpenWRT and Micheal’s page the manufacturer of the flash chip matters.

Now, off we go a’flashin….

Well broadly speaking, it all works, but there is a big gotchya here that I don’t see mentioned anywhere. Don’t use the Windows FTP client. There is no way to put this into passive mode. It’ll simply tell you the cammand isnt known (PASV or Passive) and then *if* you press on anyway you’ll soft brick the router. You won’t be abl;e to do anything until you can get a firmware uploaded. I simply moved the files onto a USB stick and booted a Mint Live distribution which worked just fine.


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