Automatic use of internal block RAMs

According to the "Specifying Initial Memory Contents at Power-Up

" chapter in the document https://www.intel.com/content/www/us/en/programmable/documentation/sbc1513987577203.html#mwh1409959590153 , the recommended way to initialize the memory is to give a default value to the signal. Check if there is any sublte difference between your code and the example given by altera that could confuse the synthesizer.