XT3 (xt1143) says 2 different microSD is write protected when the are not. One card is new, one is a year old. Both have been quick formatted and can be written to by a Windows machine.
[ "The attached storage device is write protected. Remove it, enable writing, and reboot the device."]
New card is a Sandisk Extreme PLUS 64GB
Older card is a Samsung 64 EVO