Sony Xperia 1 II

The Sony Xperia 1 II is a wonderful smartphone. While Sony put a lot of focus into the Alpha-like camera experience, the rest of the phone is great enough to make up for the “just fine” camera quality.

First of all one important thing – before you start to do anything with your phone, do the backup of your personal data. It is only for your safety in case that something goes wrong or any mistake happens. In that case you can use the backup to restore the data and try to do everything once again. Each tutorial has been done many times to verify its propriety, so just read carefully all instructions and continue step by step.

Sony Xperia 1 II (XQ-AT51 & XQ-AT52) firmware update
a) download and install the latest Flashtool
b1) download Android 10 for Sony Xperia 1 II XQ-AT51
b2) download Android 10 for Sony Xperia 1 II XQ-AT52
b3) download Android 11 for Sony Xperia 1 II XQ-AT51
b4) download Android 11 for Sony Xperia 1 II XQ-AT52
b5) download Android 12 for Sony Xperia 1 II XQ-AT51
b6) download Android 12 for Sony Xperia 1 II XQ-AT52
c) open the XPERIA Flashtool, click on flash and choose firmware, than click ok

Important – if you do not want to delete any data of your phone, just uncheck flashing userdata.sin file. All data will remain in your phone, but sometimes it can cause additional troubles. So it is better (and I recommend that) to do the backup of your personal data, than proceed with clean instalation and then restore your personal data. If you are making downgrade, your device will be factory reset, make backup first!

d) turn off your phone and when Flashtool shows pop up window, connect phone to PC with holding volume down button
e) after few minutes all is done and your phone gets new firmware