It's... inactivated.
Purah always said Sheikah artifacts weren't magic. I suppose we got the last laugh after all. The voice is dull, despite the words. Her people may still be alive, in their village secluded by the Necluda mountains. I wonder...
The air seems to congeal with a sort of thickness. The evil purple growths strewn around the space and making up his summoning circle seem to pulse. A haze of blue and violet sparks in an arc in front of him. The screen of the Sheikah Slate—fizzles. For a split second, a blue print of the eye symbol on the Slate's back flashes on the screen, but then it glitches into orange and blue lines, and then it goes black again.
The Sheikah may be able to restore it. There was ever only one working Sheikah Slate found. If your conjured copy works, you may be able to return control of Vah Medoh to me. If Calamity Ganon saw it necessary to disable the Guardians and the Divine Beasts, he must have feared them—this may be key to destroying him. If the other three Champions' souls are also bound to their Divine Beasts, and we are all restored...
The Divine Beasts were created as ultimate weapons to seal away Calamity Ganon, once upon a time, together with the Princess' divine power and the Master Sword. Link and Princess Zelda are long dead, most likely, but with four out of six, and Ganon seemingly weakened, there may be a chance.