SOPC problem using Avalon-MM tristate bridge and memory

this would be easy in Qsys, you could internally connect 1 of the RAM ports inside of Qsys and export the other so it is accessible outside of Qsys

you don't want a tri-state bridge, as you've found that's meant for external interfaces. you can create a custom component using the Avalon MM Master template. i don't think any other changes need to be made. connect your internal SOPC Builder MM Master to one port and your dummy custom component to the other. when you generate you should have the Avalon MM Master ports on your system

alternatively you can pull whatever is outside of SOPC Builder in as a custom component