Comment 1 for bug 115795

Linux is sandboxed and shouldn't be able to break the XMB beyond a settings reset (I believe), unless there was a hardware failure (unlikely). There should be an option in System Settings to reset the PS3 to default. I'd try that. I know the PSP, which uses a similar XMB OS, occasionally corrupts it's settings and usually a reset to default settings fixes the problem.

Anyhow, it's unlikely it is an Ubuntu bug.