With access to a research facility quality electronics lab, and they still haven't managed to create a functional backup on a new NAND chip.

"Unfortunately, the 1:1 backup copy did not work in the iPhone 5c. Even the boot Apple logo did not appear on the power up. There were some references to hidden partitions used in iPhone NAND storage which makes cloning a challenging task."

... keep reading

I kept reading, from what I understood they restored the copy on the original chip, not made a clone. They could use the backup process to restore a specific partition but then you have a problem of wear due to writes, they've said that a 6 pin passcode is unlikely to be able to be brute forced on a single NAND chip without inducing possible damage due to wear.

Edit: You are correct, I've misread it.