hello guys!
i bought 20 spark cores and from this 20, 2 of them doesnt work!
what i do?
i tried reset and nothing!! 
please help me!
Could you provide some more detail about your problem?
What have you tried to do about it so far?
What colors do you see? Rather than which you don’t see.
Have you tried the troubleshooting guide?
ScruffR: Fixed broken link
yes.
when i try power on the spark core for the first time, they start breathing white, not blinking blue.
i tried all, reset to factory, the reset + mode button, etc… and nothing.
is like if it were already claimed