Without more details like model numbers and such we can't really answer that with 100% certainty. However, it may not be possible, as the device may not have internal storage other than what was meant for the ROM.
I dug one of these out of the garbage. It appears to be a Shenzhen Saintway tablet. Mine has 1 GB RAM 8 GB ROM Android ver 4.6 Model # A1858. I'm curious as to whether it could be booted from the SD card.