@lakotaubp Very well, It didn't helped me as I still meet the same problem. I checked ADB and it worked fine on windows.

During the recovery mode but nothing happened inside the installer so I rebooted the phone to the bootloader screen and the same error happened again.

I'll go check the telegram channel, Thanks

I tried to install ubuntu touch on my Fairphone 4. I Used the windows 10 x64 bit version of the installer from github (v0.9.7 beta) wich I supposed is the latest version after reading this post.

There is a step where I am asked to got reboot in recovery mod from the fastboot mod and then inside the recovery mod I need to get back to fastboot mod.

I find it rather difficult to understand this step since there is no such menu "fastboot mod" inside recovery mod. closest I found was to use "Advanced/Enter fastboot/ Reboot system now".

After this step is complete I meet this error which mess with the installation and make it unable to go past this step

The error message

I reproduce this every-time. I'm not sure if it come from a wrong step. If this is a hardware problem or bug.