Flashmode

Hi,

when trying to get into flashmode to flash the new firmware by pressing the volume-down key and then pluggin the usb cable in, the phone just boots normally, but into a "safe mode". There is a overlay in the bottom left corner saying that, and most apps are gone.

Any ideas what I may be doing wrong going into flashmode? Is there another way to get into flashmode?

The device is encrypted, maybe that has something to do with it?

Thanks
Yannik

[HELP] Flashmode keeps dropping

Yesterday I was dumb enough to format my whole phone, so right now I don't have anything on my phone and it doesn't even boot, it just stuck on Sony logo and the notification bar is just red.
I thought I will re-flash it, and go back to sony's android, but I can't install it, because when I plug in my phone, it connects in flash mode, but after a few sec, it drops the connection, if my guess is right, I need to install the correct adb driver, but I can't do it, because my phone doesn't even boot up.
I also installed the drivers in flashtool's folder (windows 10 - disabled driver signature)
So, any ideas what should I do?

My phone is Xperia SP (C5303)