two days ago I tried to flash a new recovery (TWRP) and a new ROM on my Galaxy S6 (SM-G920F). I used Heimdall-Frontend 1.4.0 and also have Heimdall installed. Flashing the recovery perfectly worked, but when I tried flashing the boot.img, the process got up to about 30% and then said "FAILED!". Now my phone only shows a blue screen with this on it: "An error has occurred while updating the device software. Use the Emergency recovery function in the Smart Switch PC software."
I can still get the phone into Download mode, but the problem is that neither Heimdall nor ADB does recognise my phone. "heimdall detect" gives "ERROR: Failed to detect compatible download-mode device." and "adb devices" gives just nothing at all, although the device is in Download mode and I have installed the latest drivers. I've tried it on other laptops as well but it didn't work.
What is also weird is that the phone immediately turns off when unplugging it from USB, even though it was charging for hours.
So what should I do now?
Thanks in advance.