MAX10 and Flash Update module

If you've looked at the training on RSU and the documentation, I'm not sure why you're still having an issue. The IP has an Avalon slave interface. You set a base address in Qsys (Platform Designer) so that a master component, such as Nios, can access and control it at a certain location in that master's address map. At the base address (offset 0), you access the control bits located in the first row of table 34 in the document I linked to. You adjust the address above the base address to access the other bits (default is increase address by 4 on the master to get to the next 32 bits (the second word) of the slave).