Hello again,
Have you triend other USB port/PC ? Or other Cable if u have some? as i recommended? Push the flash means push the flash... Take your finger and gently press/push the flash drive -> The thing u should be shorting the pins on -> black rectangle thing.
Also ARE YOU REALLY SHORTING THE FLASH MEMORY? It is character
H on the picture below.
When shorting the chips you have to short them a specific way. Sometimes it is not easy and takes a while... The flash memory has two sides and sometimes it works only at one side and sometimes u have to do both... Anyways here is a picture showing what exact pins are needed to short. Look and try ! Dont forget taht u have to be connected to USB with your mp4 and turned ON.
Lemme know if it helps