The .NGC/.NGR files would be loaded from the SD card through MIOS terminal once MB_NG firmware is uploaded.
At the moment your firmware appears to be SEQ v4+ (uploaded as a hex) according to the names of the MIDI ports.
I.e. if you flash your MCU with the SEQ firmware, then you can’t perform these tests.
After the hardware is tested and working, you upload the SEQ firmware to use it as a sequencer.