Oops, I accidentally replied to Mychaela directly, here's our conversation so far, please others join in with thoughts.

On Sun, Mar 10, 2019 at 09:09:31AM -0800, Mychaela Falconia wrote:

Hi Craig,

...

Thanks again for your details Mychaela. I will read this very carefully and keep it in mind as I try to port osmocom-bb to fernvale/mediatek. I already expect a good dose of refactoring in layer1 so maybe I will touch on fixing the issue.

Have you got yourself a CMU200 instrument or not yet? A CMU200 is absolutely required if you wish to have any chance of success at your idea of OBB on MTK.

I do have a Racal Instruments 6103E GSM Digital Radio Test Set which seems to work well so far. I have tested some SIM800 modules (mtk6261) with the internal BTS. Not sure if that will fall short or not but I'll take things one step at a time. When I need a CMU200 I'll probably get one. :)

Another question: is there any way to run any official MTK-based firmware, however non-free and blob-laden it may be, on Fernvale hw?

Probably. I know from reading that Bunnie and Xobs who designed fernvale did run standard firmware/OS on some similar 6260 based devices. Maybe we could track down a good firmware and test on fernvale.

For what it's worth the fernvale isn't exactly my main target. I would much rather use a SIM800 module or eventually design of my own.

Has anyone actually done it and posted howto instructions? If not, then how do you know if the RF hw on your Fernvale kit is actually any good and not physically defective? Whoever physically manufactured those Fernvale boards sold by Sysmocom, have they actually tested their RF hw and how? And what about calibration - have they performed individual per-unit calibration of various RF parameters on those Fernvale kits like every standard GSM MS hardware manufacturer is required to?

I don't have any clue about these details. Will have to rely on Harald or maybe inquire of Bunnie and Xobs.

I calibrate my FCDEV3B boards at production time, use the calibration procedure to also serve as a test of the RF tract, and ship every unit with turnkey-working official firmware and a fully valid and legitimate IMEI, fully fit for operation as an MS on public GSM networks - do they do likewise or not? If not, then they are substandard.

M~

Thanks for your efforts, Craig