@Oneplus-3T Sorry my wifes cable was white on the chargers end and black on phones end so i guess it is still USB 1.0 and it is no good .

  Plus I booted to TWRP recovery and in wipe section choose advanced , picked everything except the bottom one and wiped , rebooted phone , went back again to TWRP recowery wipe section and swiped to format . Just this time advanced wiping and formatting returned no errors . And not like in previous attempts to wipe, everything could be ticked in advanced section and results returned with no red errors.

@saran USB connection plugs from inside white is USB 1.0 , black is USB 2.0, blue is USB 3.0 .White and black did not worked for me . I succeeded with purple . It was educational and frustrating experience for all week , but rewarding in the end .

@pglushkov said in Oneplus 3/3T:

@ziggutas said in Oneplus 3/3T:

Trying the installer with Oneplus3T but it cannot get past the 'Sending...' screen so far. I've waited for 30 mins or so. That should be enough, no?

Edit
The phone is showing Android Recovery screen with options: 'reboot system now', 'ubuntu actions, and 'android actions'. Screen is otherwise black (there was a flash of colour that looked as though it might have been the android robot lying down, but it was only there for a fraction of a second). Phone getting quite warm.

Previous experiences suggest I should go and get a better cable!

Hi all! Having same issue, stuck at this step. Device - OnePlus 3T, trying to install from Windows version of UBPorts installer. Any advice or instructions please?

P.S. Also tried to 'reboot to recovery as PhoenixLandPirate suggested - did not help.

You guys will not believe this but , I was struggling for a week with this problem and cable it is a big culprit here !
It turns out USB (connection jack heads or A.K.A. boys ) have a color code too ! Where white is USB 1.0 , black is USB 2.0 and blue is USB 3.0 .
I started with white and got errors same like you here and "connection to device is lost". Then I changed to my wife's cable it was black and I kept getting "lost connection to device" but manual flashing was with less errors . Then I decided to humor my self and tuck my daughters Huawei charging cable which was purple on connections so fastboot format:ext4 cahe & userdata start failing but Ubports installer just flyed with it with no problem ! So I got success !