@fredldotme
Before flashing with Android installed, VolDown and Power button, blue light.
After trying to install UBports, it enters some recovery.
adb devices doesn't show any device, neither before flashing, nor after.
I had Sailfish installed on this device, maybe that screws up something?

So I tried to install following your steps, but I always get this error in the last step:
Cache formatting was not succesful, flashing may fail, check your partitions on device
Where did I go wrong?

bkos@T430:~/Letöltések$ fastboot erase cache && fastboot erase userdata && fastboot erase system
******** Did you mean to fastboot format this ext4 partition?
erasing 'cache'...
OKAY [  0.012s]
finished. total time: 0.012s
******** Did you mean to fastboot format this ext4 partition?
erasing 'userdata'...
OKAY [  0.094s]
finished. total time: 0.094s
******** Did you mean to fastboot format this ext4 partition?
erasing 'system'...
OKAY [  0.040s]
finished. total time: 0.041s
bkos@T430:~/Letöltések$ fastboot flash oem SW_binaries_for_Xperia_AOSP_N_MR1_5.7_r1_v08_loire.img
target reported max download size of 536870912 bytes
sending 'oem' (220783 KB)...
OKAY [ 12.517s]
writing 'oem'...
OKAY [  3.171s]
finished. total time: 15.688s
bkos@T430:~/Letöltések$ ubuntu-device-flash touch --device=suzu --channel=16.04/community/fredldotme/devel --bootstrap
2019/10/26 21:30:40 Device is |suzu|
2019/10/26 21:30:40 Flashing version 23 from 16.04/community/fredldotme/devel channel and server https://system-image.ubports.com to device suzu
2019/10/26 21:30:50 Cache formatting was not successful, flashing may fail, check your partitions on device
2019/10/26 21:30:52 Waiting for device to enter recovery mode ...
 Cache formatting was not succesful, flashing may fail, check your partitions on deviceFailed to enter Recovery
bkos@T430:~/Letöltések$

After this the device is in the endless boot loop.
Thanks in advance.