Using Multiple FatFS Partitions with arduino-pico

[precurse]

Hello,

I’m looking to run multiple FatFS partitions with the Earle Philhower arduino-pico framework. The built-in FatFS implementation seems to support only a single partition in flash. However, I noticed the NO_GLOBAL_FATFS define in the source here:
https://github.com/earlephilhower/arduino-pico/blob/master/libraries/FatFS/src/FatFS.cpp#L34-L42

This isn’t documented, but it looks like it might allow me to manage multiple independent FatFS instances. My goal is to initialize two separate partitions, each pointing to a different flash region, so I could maintain two isolated FAT volumes. Conceptually, something like this:

FS fsA(FSImplPtr(new fatfs::FatFSImpl()));
FS fsB(FSImplPtr(new fatfs::FatFSImpl()));

FlashInterfaceRP2040 *fiA = new FlashInterfaceRP2040(startA, endA);
FlashInterfaceRP2040 *fiB = new FlashInterfaceRP2040(startB, endB);

The problem is that I cannot include the SPIFTL/SPIFTL.h or SPIFTL/FlashInterfaceRP2040.h headers to access the FlashInterfaceRP2040 and SPIFTL classes.

I was hoping someone with more experience could advise on whether this approach is feasible or suggest a way to implement multiple FatFS partitions on RP2040 using the arduino-pico framework. Or at the very least, override the _FS_start and _FS_end variables in the FatFS library to allow me to use storage before or after the FAT partition? I'd like to have have some non-volatile storage outside of FatFS that I can use.

Thanks in advance for any guidance!