Hardware Wii u sd cards

[Cart00nHead]

I have a wii u black 32gb on firmware 5.5.2 E what is the largest size sd card I can use? Is it true I shouldn't use hdxc type cards? Or could I use any size micro sd card. Also if there is a maximum size could this be increased with a hack or custom firmware?

 

[godreborn]

I have a 256 GB full-size card in mine, and it's never given me any problems.