Just an update.. I finally ran across this myself (122 MB - 128,615,182 bytes), so tomorrow CJPC is going to test it on his Debug console. As long as it's legit we will add it to our Site Downloads then.
i'm just new but i have the 2.42 debug fw and i searched a new update since long time.
Another update, CJPC was able to test it earlier today and it is (as expected) the legitimate 2.52 Debug update file.
He ran out of time tonight, but tomorrow we will make a post for it and add it to the download section.
Good news for those who wish to update their PS3 Debug/Test consoles, and also for those with Retail PS3 consoles with Firmware higher than the last 2.30 Debug Firmware... as now if theirs is under 2.52 they can update to the Debug to check out the non-functional menu options and then update to Retail 2.60 when they get bored of it.
For those seeking to install Debug Firmware on their Retail PS3 console, here are some links on how to do it: