there is a really weird thing I came to realize when debugging a non-working application for my DE2-115: Initially I had problem with running my application from SRAM. Memory test from on-chip memory works. So I started a new project based on the golden sopc example and the hello world application. This works from SRAM. However, when I add an SPI to the SOPC, I get the following problems: 1. Either Quartus reports recovery problems with CLOCK_50 or 2. timing is ok but I get verification errors when downloading the elf. What really puzzles me is: The golden sopc is very simple. I would not expect any timing problems. And since they only occur when adding an SPI but do not seem to be related to it. Honestly, I do not have an idea how to continue. Any hints are welcome.