Yes, it was promised, and as far as we know, it's still in the works.
A little note about crossflashing though...Even though it does void the warranty when you flash to a crossflash firmware, you can reflash back to your original firmware using the omnipatcher designed by C0deKing and Code6553. After the reflash, your drive will appear as if it has never been altered and therefore you can still have a warranty:) The only way you might be put into limbo is if something happens that makes the drive unable to be flashed, which would probably make it unoperable anyway, so your probably safe there as well.
On top of all this, there are "correct" firmwares available on the site that are designed for the 1633 specifically. The latest one is BS0S. All you would have to do is use omnipatcher and change the write speeds. The only one I changed was for the MKM DVD+R9 for precisely the same reason you are awaiting the new official firmware. Oh and don't forget that with C0deKing's latest release, he applied a LEDFIX, so that the multicolored LED in the drive is allowed to use it's colors. Green for reading, red for writing, and orange for buffer underrun. Incase you are unfamiliar with the history of liteon drives, the multicolored LED functionality used to come standard, until the parterning with Sony.