Hm, strange, you could go for the version A1 released, but are you really sure, that this link is not working (does for me)
Have you tried here in or DL section?
BlackberryOS.com - Downloads - 9500_188.8.131.525
link is this one:
Since you've asked via user message: What I could recommend is the 184.108.40.2065 (to be found here: BlackberryOS.com - Downloads - 9500_220.127.116.115), I have used it immediately when it became available and it was a major step coming from 4.7.x.x - it's much more responsive. Please check here for the how-to: http://www.blackberryos.com/forums/b...es-videos.html
425 should fix many of the issues you are describing!