Firmware download
Click and download:
AF 25mm f1.8 Fireware VER 1.08 for X mount Fujifilm Cameras
AF 25mm f1.8 Firmware VER.10 for E mount Sony Cameras
Upgrade steps:
1) Download it to your computer;
2) link your lens to your computer through the USB-C port on its side, and it should show on your computer as "SG-image";
3) Copy and paste the firmware from your computer to your lens, and that's it.
There is a txt file on the lens which shows the firmware version and its release date. It should show the firmware version you upgraded it to.