I would normally recommend the secure erase option in the BIOS, but since your meegopad doesnt power on anymore thats no option.
I dont think you can erase it without opening up the device, maybe you can try to connect a programmer to the storage chip and erase it. (dont know exactly about programmers)
Also, keeping sensitive data on a computer with flash storage (eMMC) is not really a good idea.
Most company's use Encryption & drive wiping software for their sensitive data, so i'll suggest you dont use computers with flash storage like eMMC's unless you"ll use encryption for your sensitive data because drive wiping won't work on eMMC's, it will only degrade the storage chip.