Xperia XA2: Stuck on "Sending 'boot.img'" I unlocked my bootloader, and did:

sudo adb reboot bootloader
sudo ./fastboot boot ~/Downloads/twrp-3.2.2-0-pioneer.img


But it gets stuck on sending:

creating boot image...
creating boot image - 10240 bytes
Sending 'boot.img' (10 KB)


I'm doing this on Linux and using the latest platform tools.
Apparently the XA2 doesn't play well with Linux and USB 3 so I solved it by using an old laptop with USB 2.0
https://together.jolla.com/question/193348/xa2-flashing-issues/