how long does a reboot download for galaxy s7 take?

[Android Central Question]

Screen shows arrow in box and says do not turn off target. It's been almost 2 hours that way.

 

[B. Diddy]

Welcome to Android Central! You're in Download Mode, which is intended for transferring a firmware file from a computer via USB connection. It's typically reached by pressing and holding Power, Home, and Vol Down when booting up.

As long as you're not connected via USB to a computer and actively downloading a file, it's safe to force a shutdown by pressing and holding Power and Vol Down for about 20 seconds. Then power back on normally.