Request for Debugging Method Guidance for FIDO Firmware

[devi1207]

Hello Polhenarejos,
I am working with your FIDO firmware project(version 6.4) on the RP2040 and trying to implement debugging to understand the firmware's flow. I attempted using UART for debugging, but it only displays statements from fido.c, I could not debug cmd register and cmd authenticate etc.Also i tried with tinyusb cdc method for debugging through print statements but fido process is being affected.Could you kindly guide me on the preferred or standardized debugging method to log the entire firmware effectively to understand the fido process completely?

[polhenarejos]

I do UART debugging too. cmd register and cmd authenticate are for legacy U2F, so it will depend on the web you are targeting, whether is CTAP1 (U2F) or CTAP2.
Debugging TinyUSB is only useful for low PHY level. I usually do not debug it unless there's a problem with USB protocol stack.
If you build the firmware with DEBUG_APDU=1 debug will be more verbose.

[devi1207]

I want to understand fido2 and u2f functionalities wrt CTAP1& CTAP2 protocols.Also can i test fido2 and u2f one at a time from device side and web browser side.Could you please suggest me the methods to debug?