Simplest way to write to USB stick or TF/SD card with PBP?

[CuriousOne]

So I just disregard these pins and let them float?

[tumbleweed]

Look at the SERIN2/SEROUT2 commands in the manual.
They allow you to specify optional flow control pins which you would connect to the RTS/CTS pins of the module you're using if it has hdw flow control.

That may or may not work since the SERxx2 commands are bit-banged.
SEROUT2 would probably be ok, but SERIN2 might have issues.

[CuriousOne]

Thanks, I'm only going to write to flash drive, so I'll need SERIN for just status checking, whenever drive is physically present.