@marathon2422 That's it! By using the BQ flash tool i could reawake my device.

Unfortunaltly i had to flash my device with am android package cause BQ don't provide an ubuntu package for the HD edition anymore. Afterwards i could reflash the device back to UT by using the UBPorts installer!
Now i'm glad to have a running device and i stricktly avoid to power it down...

Btw: after reflashing to android the battery power was only 1%. This after shutdown only 48h before. So the shutdown was defintly incomplete and the device drained the battery strongly.
My question now: is this a BQ problem? Or is it a UT bug?

Thanks to all for giving me tips and advices! Now i can restart with UT

@pulsar33 I tried your tip serveral times thie evening, but it doesn't work until now. Maybe i'm too impatient Pehaps 5 minutes are not enough...

@andromeda I have a LiPo charger/discharger. I thinking about discharching the battery. But therfore i have to open the battery to bypass the protection circuit ...

@marathon2422 said in BQ Aquaris M10 HD won't turn on:

(...) ,make sure it goes off (...) it needs to go completely off (...)

but how can i force a complete shutdown? The screen is totally black, but the cpu is a little bit warm, even 2-3 h past turn off.

@advocatux I connected the device for > 4h to the power supply and i tried to start serveral times but it still doesn't start...

Hi,
I flashed my new M10 HD Android via UBPorts-Installer with UT 15.04. Installation & Reboot ran well (resize /cache & /system partition was neccesary). Afterwords I played with UT for about 2h. Battery power 60%. Then I decided to power down the device to insert a sd-card. I tried to turn on the device again, but nothing happend. I pushed the power button several minutes, no reaction. I also tried serveral combinations with power button and volume +/- . The screen stays black, no vibration, absolutly nothing. Also no reaction when I connect the device via usb to my desktop pc. Adb says “no device found”.

Now i ran out of ideas. Can anyone help me?