The failure of the LTR-24012b is not due to firmware at all. It's due to a bug in the mediatek chipset. The last 2 indicates the LTR-24102b uses chipset version 2. I know versions 5 & 6 can burn Safedisc 2.9. Version 3 MAY be able to. I am still unsure as I know noone with a Version 3 drive.
Please note this goes for ALL drives made with the mediatek chipset, including Asus and Mitsumi.
So if the Mitsumi uses latest Mediatek chipset (5 or above) it can handle SD2.9 just fine.
However if you watch for deals in stores like Office Max, I just bought a Cendyne 52x (model LTR-5226S) which is a rebadged Liteon for $9.99 after rebates. I would suggest getting the Liteon.
Asus makes a good 52x burner, but if you burn Securom based games with any form of the twinpeaks method, you will have to burn a second disc to install it, while Liteons can install from it just fine.
Just my opinion...