VERY GOOD NEWS SDXC!!!
TRY AT YOUR OWN RISK... NOT OFFICIALLY SUPPORTED AND I AM NOT A PRESONUS EMPLOYEE NOR A PAID ENDORSEE... FOR ENTERTAINMENT AND INFORMATIONAL PURPOSES ONLY!!!
FYI - update - While I know this is still never going to be officially supported, I have discovered that using Sandisk Extreme MicroSD XC I V30 U3 A2 rated cards of the following sizes: 64GB, 128GB, and 512GB test perfectly every time tested as good for the max 34 track simultaneous audio recording on my Series 3 SL32 board. The key seems to be using the following for wiping and formatting the SDXC micro cards:
I tried several formatting/partitioning utilities/softwares and found that AOMEI Partition Assistant Standard Edition works every time where ALL others fail with SDXC cards. I have only used the "write 0" wipe option once. It is optional so far but I wanted to test all methods. Whether I just deleted the exFAT partition and then performed adding and formatting a new FAT32 partition or first did a "zero" bits wipe and then created/formatted the new FAT32 partition, all 3 of these SDXC drives tested perfectly over and over for 34 track capable write speeds on the StudioLive 32 Series 3. Just FYI...
Hopefully I'll eventually get around to actually writing 32 simultaneous audio tracks if I can get enough people to participate or find someone with audio splitters so that less sources can feed muiltiple audio inputs at once. The most I normally record at once is 12-18 tracks.
These 3 cards were purchased brand new straight from Western Digital/SanDisk.
I have photos of the cards and results on the Presonus Forums in the SD thread under the Live Sound forum under Series 3 mixer area.