Try to remove the battery and press the power button-press at least until the power stored in the transistor can be lost or silenced for a few hours .. reattach the battery and immediately try to enter recovery. if you can not immediately escape .. and replace the battery .. try again, that's what I do when RAMDUMP already.
*nb: don't try enter recovery while charging or connected usb on PC
sorry for my bad english
Maybe... this could help: