MicroSD card compatibility in Android AOSP
14 Feb 2018
MicroSD cards of the SDXC or SDUC variety with capacity of 64GB and up must be re-formatted as FAT32 with large sector sizes to be recognized in the Android AOSP (Open-Source Project) operating system such as on the Archer 3, Allegro 3, and Mesa 2 Android platforms. The default exFAT or NTFS format of these cards will not be recognized.
To format a drive to FAT32, attach the drive to a Windows computer, right-click on the drive letter assigned to the drive, select Format…, make sure File System is “FAT32 (Default)”, and then click Start. Once it is finished, that drive can then be attached to and recognized by the AOSP unit for storing and transferring files.