1. Download the OS file to the PC, and connect the RT40 device to PC with a type USB cable.
2. Copy the OS file to the internal storage of RT40 device
Note 1. you need to pull down the notification menu and change the usb preference as “file transfer” to allow PC to access internal storage;
Note 2.Please no need to unzip the OS file.
3. Setting-> System-> System update->Local updates-> find and import the firmware file-> follow the tips to continue until it reboots successfully.
Note 1: Please do not import the OS file directly for recent file list, but import it from internal storage indicated with an arrow in the figure below .
Note 2: If the current Build number is a version released before March 23, 2022, please upgrade to the interim version first SQ47_EN_XX_WE__DS__R01_U_220323_01_dev.zip: https://mega.nz/file/6aYgXDJQ#VGCgbCarzrFFQQi1WtjrR4krlO-QnLCILzKooIelhvA, and then update to the latest version.
4. After restarting, check the build number at Setting->System->About phone->Build number, to check whether the OS upgrade successfully