I'm wanting to play PAL games off my NES Everdrive at native 50hz. I switched to PAL mode in the AVS' menu, but all I get is a black screen after booting the cart (when I should see the Everdrive menu).

Is it just my TV? Or is it because North American TV's in general typically don't support 50hz?

I'm using firmware 1.20b8, an Everdrive N8 (NES), and playing on a Samsung plasma TV (2011).

Both. Your TV does not support 50hz, and many TVs bought here won't.

Yep, it depends on the TV. I have two flat screens at my house. My primary gaming TV does not support 50 Hz but the other one does, so I have to drag my AVS upstairs if I wanna play PAL games.

Many NES games weren't optimized for 50 Hz anyway

If you want to accurately play the NES PAL exclusives, then you need the AVS to run in PAL mode.  They are ALL built on 50Hz.   
 

What games/ROMs were you testing?  I know for a fact that my TV supports 50hz PAL mode (forced by RetroN 5 into that mode before my AVS arrived, then confirmed with the AVS) and can give it a shot.  However, if you've switched the AVS to PAL mode and still get the menu, then your TV should actually be supporting the correct mode--the menu as well as games run in 50hz when set to PAL, at least on firmware 1.10 (last time I updated and checked out PAL on my AVS).  I wonder if you've just got some bad ROMs?

It's gotta be my tv. It's a black screen with a message saying "mode not supported".

It's definitely not a ROM problem as they all play fine from the everdrive @60hz but look/sound sped up.

 

Nope thats wrong    Newest firmware update keeps menu in NTSC when you switch to PAL for games.

Ah, well, that's good to know.  My TV actively reports which mode it's in what frequency and resolution it's running at, so on 1.10 (which my AVS is still sitting on) it definitely went to 50hz when I updated the setup.  Please note that I did note "at least on firmware 1.10 (last time I updated and checked out PAL on my AVS)" to buffer my response--thanks for the heads up about the newest firmware.  I'm guessing the change was made due to people with incompatible sets jamming on buttons during the test period after changing from NTSC to PAL and locking themselves in that mode?

I might need to try firmware 1.10 just for the hell of it.

Bumping this up. So it turns out I have an extra Memorex LCD TV and Alienware gaming monitor that can do 50hz. So I was able to switch to PAL, start the everdrive (no more black screen), and play a bunch of european exclusive games in native 50hz which was really nice  

Makes the AVS even more awesome to me.