I like an old Linux distributions. Now I’m using SLED 11 SP4.
Some time ago, I tried to upgrade Debian 5.0. I’ve upgrage Glibc from 2.7 to 2.12, then to 2.15 (for Steam). Also upgrade kernel, Qt, ntfs-3g, Firefox.
On Ubuntu 12.04.5, Firefox 38 + Flash Player + VDPAU aren’t crashing. I had used DEB-SRC for upgrade the kernel (3.16 from Debian Wheezy) and Glibc (2.15 from Ubuntu Precise) on my old Debian. Flash Player works with an old Glibc, and crash with the new Glibc.
I can capture a video, where Flash Player are not crashing with Glibc 2.7 and 2.12. And crashing with 2.15 (however Glibc version is same with Ubuntu). Also I can put there ISO image.