I recently purchased a used Meade LX-200 telescope, which uses an AutoStar II handbox.  Unlike the  Meade #497 AutoStar controller used on my ETX-125 telescope the LX-200 uses a 6 pin plug for the RS-232 port, and it’s located on the main box, not on the handbox. So if you have a Meade #505 cable (4 pin) it won’t fit correctly. I purchased a Meade #507 cable, which is electrically the same (a RS232 to USB connector) but has the proper 6 pin (larger) plug for the LX200 GPS RS-232 ports.
[Having this cable will also let me control the telescope via software on my computer if I want, so I think it was worth the $20.]

It already had the latest 4.2g (note the lowercase g) firmware from Mead installed (which is good, as Mead is now out of business).  However, I used the starpatch software along with the PatchLX42ggv22.spf and BuildLX4.2g.rom files from the very helpful StarGPS company to patch the 4.2g firmware with a few bug fixes, including the GPS date rollover fix.  [They are very generous in that the trial version of their software will patch all the bugs, although if you want to use it to add in support for a GPS receive to a telescope that doesn’t normally come with it like my LX-200 GPS does, then you have to buy the license key.]

This process took me a full hour of downloading time, because I set the speed to the lowest 9600 baud to give it the best chance of being successful on the first shot. (I ran into issues with my previous firmware upgrade of the #497 handset that was fixed by using 9600 bps.) When it was done, I had the  4.2G (note the uppercase G) firmware installed with patches.  This also enabled the “Smart Mount Technology” option from Meade, which is nice to have available, even if you don’t use it.