What is the "No-Flip" mod?

[oggie]

You're better off getting a drive that has already been modified and calibrated/aligned from Sncboom2K!

But to be clear, you don't need the no-flip mod to still get full use of SCP?  You just have to deal with flipping the disk, correct?

And the ignore sensor is separate from the flip mod, right? It needs to be done regardless of the flip mod, correct?