WLToys Q303

Hmmm that's weird, with this option enabled your should be able to select output power.

Ok, I've a theory why only binding seems to work but I'd need a capture from a stock transmitter that's using lower RF frequencies to confirm ...
Yours is using frequencies 2472 MHz and up and I found this could be a problem when emulating the xn297 with a nrf24l01, especially with 250kbps bitrate...
I can make a build that's using the id / frequencies of your CX35 which are in the 2410-2429MHz range, but we're still not sure they're both using the same id / freq mapping.

Yes, also try this build that has the same txid / channels than your CX35:
www.dropbox.com/s/t34xxg6o6ii0bk0/deviat...f3e_cx35_ID.zip?dl=1
Don't expect it to work with hte CX35 tho, they're not using the same bitrate + other small differences.

Maybe I'm totally wrong and there's a mistake in my code, but I checked with an emulator build + some debug code, the output is similar to what you captured from your stock TX.
github.com/goebish/deviation/blob/protoc...ocol/q303_nrf24l01.c

No problem, meanwhile I'll add the CX35 format option, it's only slightly different.

Here's a test build (devo 10) with the ID/channels of the 2nd TX and a few other changes:
www.dropbox.com/s/2fbzy1orsep8vxu/deviat...af3e_2nd_ID.zip?dl=1

No, I think direct support for XN297 will never happen

Are you using a x-in-1 module ?
Any chance you can try with a separate nrf24l01 module ?

I know some people are having issues with the 4-in-1 running the E010 protocol, which is using a XN297L at 250 kbps as well, no problem with "original" nrf24l01+.
Looks like the x-in-1 modules are using fake nrf24l01+, which doesn't support auto ack (not required for Q303 tho).

The XN297L documentation is pretty clear (better than non L version), I only have a Chinese version but google translate is helpful and it's quite similar to nrf24l01 except for a few registers

I don't think that will help, the nrf24l01 doesn't have those extra modem settings anyway.

I can compare the Q303 XN297L settings with those of the E010, but that takes quite a bit of time and I don't think that's really useful, I'd really like that you try with another nrf24l01 module first

I've just ordered a XN297L breakout module, so if we can't get it to work I'll be able to configure it as a receiver with the same settings and check if it can receive packets from a nrf24l01.