quectel_eg25_recovery

Following the discussion on illegal cell tracking where several comments mentioned the firmware can be a problem, here's a link to a free-software firmware. I believe this is important, because on Android the firmware controls the network connection (and GPS, etc). It has its own embedded Linux, flash and CPU so even if you have root and run a firewall on android, it can send packets that will not be visible to the android kernel. Most firmware have adb and fastboot, which can be used to replace what's running there by something you can recompile and audit. If you don't like it, you can also restore the initial firmware, for ex: https://github.com/Biktorgj/quectel_eg25_recovery EDIT: replaced baseband by firmware. I confused one for the other. For context as to why it matters, see https://news.ycombinator.com/item?id=36658078

> Any other related rererences - the tech that enables this sort of tracking? It's everywhere in mobile devices. It's better not to use them. If you must use one, you must at least have root to disable AGPS + add stringent iptable rules to disable any outgoing communication by default: you should only enable connections per app, or per IP/domain for what you need. Still, that'll be of a limited help since the baseband manages connections (3GPP profiles etc) and does the equivalent of NAT to your device. For all I know, the baseband could tell android "location disabled? sure thing!" while still getting GPS fixes + sending the position by UDP packets processed by the baseband OS: Android won't even see it! Yet by virtue of sharing the same IP (or being "enriched" with your IMSI as you can see above), you will be totally trackable. Doing an

So I got a little bit of time to check (https://github.com/Biktorgj/quectel_eg25_recovery/tree/EG25G... - the NON-HLOS), and it's still actually running a Qualcomm Hexagon baseband (40mb binary by Qualtec when combined using Gal's unify_trustlet script). Load that into Hexagoon IDA plugin and you'll see it's bog standard Hexagon for all the remote GSM/LT code that actually does stuff (similar to the project zero research). I haven't verified (and don't own a Pinephone) but most Quectel boards I've seen in the past do enforce signature validation, so binary patches are not easy.