I want to flash a special disk image onto an Android Emulator (Google Pixel 2) using adb and fastboot. The virtual device can only be detected by adb but not by fastboot. I already tried (cmd as an administrator):
C:\windows\system32>adb devices
List of devices attached
emulator-5554 device
C:\windows\system32>adb reboot bootloader
C:\windows\system32>fastboot devices
C:\windows\system32>
I am using Android Studio (Android SDK and Google USB drivers are installed properly, i also enabled USB debugging in the emulator) on Windows 10. Is it possible (in principle) to use fastboot together with an emulator? If yes, do you have an idea why it does not work here?
No, you can't use fastboot with Android Studio emulator. AVD does not have a bootloader, it just boots the system and ramdisk images.
If you want to use fastboot, you'll need a real device that supports it (mostly everyone but Samsung's).
You may find more information in this post: how to reboot the emulator into recovery mode