Chosen Solution
Can the 32 GB be upgraded on the Samsung Galaxy S6 Active mainboard, does it use a micro SD card?
No it doesn’t use/provide for microSD cards. The 32Gb flash memory is PCB mounted in a soldered on ball-grid microchip which possibly could be upgraded to 64 or 128Gb BUT would require expert SMD soldering skills not to mention sourcing a chip supplier.
You could try getting a very small OTG to mSD adapter and hiding it in a rugged case. Thats what I did with mine. 32+128. Could be more if I had a big case, hollowed it out and plugged in a hdd. But at that point I just use a Note, otg, my passport. 32gb+1tb for music storage and car music.
