hii.. i am working on beaglebone black. I was installed ubuntu in eMMc of it and i can't get the desktop environment of it then I was formated the beaglebone black after formating when i was connecting it to my pc it was not shown like a device and ssh was also not working then i was trying to install another OS on eMMc it was not booting .I was also trying to boot from microSD card but it was also not working. tell me how can i restore the all things in eMMc due to which it can work like just i brought it.