Nintendo DS Freezing on Boot-up!

Help! My Nintendo DS freezes when booting up even when there’s no cartridge in either slot.  On the top screen, the NDS logo animation loads, then goes to white.  On the bottom screen, just white (no health/safety message), then it changes to red.  Both screens are then frozen while power button green.  This means I can’t access the system configuration menu.  :(  Has anyone seen this before, know what this means, or how to troubleshoot this issue?

Some background on the issue… the problem began yesterday.  I was attempting to enter the system config. menu, but found the console would freeze after clicking the menu icon (this worked fine the previous day!).  After only few repeated attempts and reboots later, the NDS suddenly began to freeze during boot up as described above.  Interestingly, I have a “Super Card SD” and the content on that cartridge (slot 2) successfully loads/plays flawlessly. Am I correct to assume the system reads slot 2 first by default? Because the “Super Card SD” works, I believe it’s not an issue with the screens themselves, or those internal connections (which were suspect as I’ve replaced the bottom screen a few months ago).  I’ve also tried fully charging and then switching the current battery with a spare, and no difference.  To add to this, I just recently acquired, setup, and have been using a new R4 card, for the past few days with no issues.

Could the R4 card have corrupted something internally?  Is there an alternative way to do a “safe boot” and access the system menu/files?    Is there some type of firmware I can use in place of the system interface? I’d love to salvage this thing and get it to work if I can. I’m about to open it up and examine the boards/ribbons for anything suspicious. Any insight would be greatly appreciated.   Thank you!