Uncommon usage, technical
jargon, verb, meaning 'to erase'.
Comes from 'eeproms' (Electrically Eraseable Programmable Read Only
Memory) units in days of yore which were 'flashed' so they could be written on again. Typically, a computer
geek would understand this usage.
PC Onwer: "So, should I through my broken computer in the
trash?"
Technician: "Make sure you flash the drive first, for security reasons."
PC Onwer: "WTF?"
Tech: "Uhh...erase all the information."