this is just provide some basic background info as I keep seeing people ask about why and trying to find workaround.
in early years of SD card development there do have hardware limitation,
I got a Olympus LS-10, released on 2008,
initially only support 8GB, later upgrade firmware to expand support to max 16GB,
SD max 2GB
SDHC max 32GB
weird limited by hardware.
and it have some gotcha with firmware bug like
if you keep it recording to full, you lose all data, if you lost power, you lose all data, etc,
but still serve me well as my last backup.
nowadays we have all new fancy recorder product lineup, and card are so cheap, why still 32GB?
you can even try a SDXC card on modem recorder and it recognize but refuse to let you use it's full potential, whyyyy??
the answer is so simple, MONEY,
SDXC standard require exFAT support, exFAT license is owned by Microsoft,
so if your device wanna support exFAT, you have to pay the M$ tax, for each device you sold,
then go through the development process to verify the exFAT support.
as the storage requirement on audio recorder doesn't scale like smart phone,
there is little interest to pay extra bucks to support it.