Rooted, but su hangs

I've had my phone rooted and flashed/reset/reflashed it several times in the last couple years. However, I recently reflashed to the stock image found here . When I try to use SU apps, it prompts to allow, I say yes, it seems to proceed as I'm used to, but nothing happens. So I open up trusty terminal and get a $. I type su, prompt/approve, but it just hangs. I never get a #. No error, no permission denied, nothing. I'm assuming this is the underlying cause of why SU doesn't seem to work for anything. I've checked and confirmed that setuid is set: -rwsr-sr-x root root ..... su So I'm kind of at a loss here. Any help would be appreciated.