Is anyone working on an open hardware 3G/4G dongle?

Might be only a bit related, but osmocomBB [1] is a quite complete project that implemented an open baseband library.

It can be installed on a lot of old dumbphones and allows to create a base station and mobile station. Might help you to understand the inner workings of the network protocol quirks.

Back then it was known to be _the_ project to easily build an IMSI catcher, so its scene got a lot of redteamers using it.

There is also an ongoing effort to reverse engineer the usb modem of the pinephone, but afaik it's still a lot of work. [2]

[1] https://osmocom.org/projects/baseband

[2] https://github.com/Biktorgj/pinephone_modem_sdk

Observer, not participant; but:

It's my understanding that the FCC and equivalents make it almost impossible for there to be open hardware that connects to the phone network. And any cracks they haven't filled, Qualcomm has NDA'd the documentation for.

see https://osmocom.org/projects

Depends how open you mean. For a lot of hobbyists and integrators, this works:

https://github.com/hologram-io/nova-hardware

And run this on a Pi:

https://github.com/hologram-io/hologram-python

If you need something one layer deeper on the module or chipset level, there’s not really a lot out there.

The most mature (4G/5G) project would probably be https://github.com/srsran Couple it with a LimeSDR and you'd have a fully open HW/SW stack.

Not exactly a dongle but something like this?

https://bellard.org/lte/

One could be made with the pinephone modem. I believe its running a version of android and people are working on reverse engineering it right now. The chip is a little big for a dongle so you'd end up with something kinda like the OpenModem in your link there.

"Introduction to open source private LTE and 5G networks" might have some pointers: https://ubuntu.com/blog/introduction-to-open-source-private-...

discussion: https://news.ycombinator.com/item?id=27946947

If the baseband and associate chipsets are isolated on the other side of a USB connection, why not use (any old dongle) and isolate it with some kind of USB "condom" with configurable "firewalling" ?

In fact, I believe I have seen such devices for USB development - a configurable passthrough USB interface that would allow you to control what gets sent over the interface.

That kind of a setup would be much, much easier to develop and safeguard than developing a modem/baseband from the ground up ...

Just curious, what would the advantage of having an "Open 4G USB Dongle" be ? Why not just get a Ublox or similar module ? Even if it's open you still have to pay usage on the carrier's network.

This was posted a little while ago, and might interest you: https://news.ycombinator.com/item?id=28051005

https://blues.io/products/