Hi is your tablet version v3c, it should be at the back in the serial number if so, then is the right firmware, if not, looks like you have bricked the tablet, is the tablet totally black or someway with a light but no image whatsoever, if it has some light on it, go to onda.cn, download the right firmware for your tablet and flash it again using the aml tool. If there is no sigh of your tablet turning on , not a light and when you try to put it on download mode in the pc it doesn't shows off, then is a hard brick, probably you will have to send it back to the manufacturer and enforce the warranty, as I did last time, turns out I mess with the battery when that occurred to me.