Logo uploading is working fine, you just have to have permissions to save files to administrator/images/ folder, and also you have to close the MC params to see it changed.
I chmoded to 777 and there is no logo in sight. No PHP error messages either.
I'm pretty sure it worked with the previous version since I was using a custom logo, but maybe I just overwrote the current one and that's why it disappeared with the upgrade.