@CamilaSouza That was the general consensus from several other persons too.
The original attempt was with v3.10 and subsequently I tried v3.6 - each failed with a different error message. Haven't had time to inspect the EI code (or perhaps it is beyond my expertise).
The suggestion to lower the rate was tried too without success.
Since there are other projects where I can apply the Spresense hardware (and Edge Impulse works fine for me with other boards), I'm going to deviate from my original plan and get the LTE extension board to do an alternate project.
Sorry for the late response. Thanks for your support as usual.
Did you come from the Hackster discussion page?
Please check the connection between your main board and your extension board. If the connection is not properly done, you might have issues with the SD card.
if you did come from the Hackster discussion page and have already tried all the tips on those topics.. Then I think you might have a hardware problem with your sd card connector. Do you have a access to a multimeter?
It's okay, I don't see any problems with that.
reserved0 and reserved1 are not being used in this current version of the SDK. So yes, you can use those spaces freely.
It is important to note, though, that if you were to eventually update your SDK to a newer version, you'd have to check if those spaces are still not being used.
@CamilaSouza It would be better if the M0+ cpu enabled a window into the 4MB SPI flash or allowed r/w access without buffering in ram. The farapi to r/w files off the spi flash is not enough (fw_fm_rawread presumably).
It also cripples the processor when it comes to loading ML models or executables from storage. It's hard to see why the platform is advertised with 8MB flash if only half actually works and is not actually enabled for access per the manual.
Thanks for the info on the Flash.
Also for pointing me to the example for polling. I had a look at it and interpret it as an idea to communicate between modules that have been started by different threads.
To use the Arduino IDE was my self-imposed guideline for my project. However there are limitations, so I do not always stick to it. So it is fine to follow SDK examples.