There's no need to flash a burner, just to swap from a PC to a Mac.
Is the burner working?
The cache not showing may be simply cosmetic, and not actually affecting anything.
That burner is more than 4 years old.
The more effective upgrade for your G4 would be a new burner, which would be much faster than the older drive that you have now. You can get a brand-new dual layer burner for less than $40 - one that you know will work, rather than installing a used one.
Here's a new Pioneer, although you really don't need to get one that's sold as Mac-compatible. http://eshop.macsales.com/static_pag...mirror_dd.html
Most burners will work, if the correct bus connection...
Here's the same drive, even less: http://www.newegg.com/Product/Produc...82E16827129043
Serendipity is a lucky guess !