I just did a fresh install on my now old Sony Xperia XZ1 but had problems with the instructions to install over ADB. The solution that worked for me is to put the iode’ zip file on the micro SD and flash from there but I was not able to get the Lineage OS recovery to do that. I did it years ago with TWRP and that’s what I used for this and it successfully flashed that way.
Go to the official TWRP page for pioneer or the Sony Xperia XZ1 and they have a port and download latest (I used twrp-installer-3.6.2_9-0-pioneer.zip):
then follow the iode’ installation instructions for the Sony XZ1:
https://iode.tech/en/iodeos-installation/#1611161940312-d722f43c-afdc
On the installation page substitute this for 5:
fastboot flash boot twrp.zip
Follow the installation instructions and this details number 8:
You need to go into Wipe to Factory Reset and then go back home.
Omit number 9 which is the ADB flash and do this to flash from your micro SD. Go into Install and Select Storage as Micro SD card and pick the iode’ 3.1 zip file.
After flashing I went back home, reboot, power off.
Once powered off it will boot into iode’ with nothing else to do.
I hope this helps!