275w ago - Update: Per Jeff Rubenstein (Social Media Manager, PlayStation Blog): In case you were wondering what it's all about, the operating stability of some online PS3 titles has been improved. Hope that clears things up!
It's now official- Sony has indeed skipped a retail release of PS3 Firmware 2.15 (Debug) in lieu of PS3 Firmware Update 2.17 which is out now via Network Update or below!
There isn't an official changelog available yet, but it appears to be primarily a bugfix update at this time.
Also, for what it's worth a little birdie told us Sony Devs already have 2.20 so perhaps another quick update will follow soon? :P
Stay tuned for more PS3 Hacks and PS3 CFW news, follow us on Twitter and be sure to drop by the PS3 Hacks and PS3 Custom Firmware Forums for the latest PlayStation 3 scene updates and homebrew releases!
Not sure why you would need to update to install YDL. I haven't installed the latest version yet so can't be 100% sure. Go over to the Linux forums and check out some of the threads over there for help.