SD cards come in a variety of brands, speeds, and specs—not all of which are suited for use as internal storage. Setting your SD card as portable storage is strongly recommended for a better experience.
As phone storage has expanded on newer phones, manufacturers rarely support SD cards as internal storage. HTC has followed suit with models such as
HTC 2Q9U100. Using SD cards as portable storage instead gives users a better experience overall. That’s why internal storage for SD cards will no longer appear in new devices.