I couldn't agree more.

Got an XA2 and thought I'd try and get ahead of the game by unlocking the bootloader, Device manager shows up an uninstalled Android device rather than a Sony fastboot driver, but despite downloading the Sony XA2 USB driver I wasn't able to install the USB driver. Using Emma shows up a locked device (the bootloader is definitely unlockable, I have checked). Has anybody else tried to unlock the bootloader on the XA2 yet?

Well, i am not familiar with how to flash on (your specific config/install of) windows, but it sounds like your device has booted into android and you could use ADB via usb with set up windows drivers from the state you describe?

To unlock you need to use Fastboot, a simple common flash tool for all phones. I compiled a windows version of ADB+Fastboot from googles sources and packaged here.
You would need to boot the xa2 into fastboot mode so the fastboot command on your pc can connect to it.
1. Power off
2. plug in usb to pc
3. hold volume down on the phone
4. plug in usb c (from pc or power source)

Entering fastboot mode should also work without cable, simply by holding volume down during off state and then press power button with vol down held until fastboot menu appears.

If connected to pc, you can check with issued in your windows console/cmd from same folder than the fastboot executables are located (extracted from linked zip).

If you have a working ADB driver on your win pc, you could also activate ADB on the phone in developer settings (hidden behind 7x buildnumber tabbing). Then command should reboot into fastboot mode without the vol down trick.

But you should look into how to backup your TA partition before unlock/flash if you plan to reinstall android anytime.

To actually unlock a modern sony with fastboot, you will need an unlock key like described here.

@mosen it need enable debugging option before shutdown the phone to connect with fastboot?

sf 2.2.2.a.b is expecting delays. lot of improves in camera.

"enable debugging" is to activate adb on the phone.
ADB is not needed if you do the vol down hold -> power on trick to boot into bootloader/fastboot on the phone.

ADB can be ignored and just adds confusion.
If you read the instructions from sites like i linked, they only use ADB to enter bootloader to not make the user miss the finger combo i guess...
ADB generally is a kind of shell running on android you connect from your phone to. You can do things like copy files to and from the device and reboot it as done here. But setting up adb and confusing modes is what fails for most users so i would advise to ignore adb.

1. install sony usb windows driver (i guess. maybe only for adb but may be needed for fastboot permissions?)
2. "finger" the phone into bootloader/fastboot mode
3. extract linked fastboot zip to pc
4. from extracted folder issue fastboot commands

thanks, just to make sure.

Hint to german locals, i snatched the XA2 just now from saturn for only 219€, offered only until 09:00 this morning.

EDIT for those who missed:
229,99€ here:
https://www.guterkauf.com.de/de_DE/p...lock-blau.html

and here: 226,99€
https://techkiste.com/products/21543

Any source?

@carlosgonz

From my experience with Xperia X :

- fastboot only works if the phone is unlocked (and thus the TA fried).
- on stock Xperia smartphone, the only combo that works is the combo that bring Sony's proprietary flash mode (so either using the free "Flashtool" or Sony's Emma, but no fastboot)

Well, yeah. That's what confuses users. Sorry to be part of it. Both is possible.
What i described was using the linux tools on windows. This works, but as i read the official install instructions again, Jolla seams to utilizes Flashtool on windows and fastboot in Linux instructions to unlock.
Now think about windows users asking linux guys how to flash. confusion confusion

EDIT, screw above... I was right. Read it again thoroughly. To unlock the bootloader they use fastboot in all instances. So the confusion for me is caused by windows needing the sony propriatary tool at all... Technically they could strctly rely on fastboot fo the whole job, but overcomplicate things with a "convenient" extra tool. Maybe needed to overcome windows permission problems?