My IBM 1410 FPGA project now features a working 1401 mode as well, with the flip of a switch, exactly like the original IBM 1410. There are still a few real problems (e.g., Console I/O Input under program control doesn't seem to be working), a few minor issues involving console problems when doing control operations, and lots of changes I want to make to the PC console support program, which really should be done before tackling I/O devices. There are posts relating to the debugging of the 1401 side of things towards the end of the list that appears on page: https://www.computercollection.net/index.php/ibm-1410-fpga-implementation/ JRJ