did you boot using the file above?
--------------------- MERGED ---------------------------
back in the day using my old r4 you could autoboot by naming to default.nds or boot.nds, i dunno what kernel your r4 is running, though that _ds_menu.dat should allow you to boot directly in to moonshell, but you will be running moonshell instead as your r4 kernel. as i used moonshell before mp3 players and smartphones became everyday commodities i had it able to autoboot straight to moonshell after the cart and kernel booted (no r4 menu), though im talking about 5-10 years ago, it also depends on who makes the card since they can "lock" the card from loading other kernels (r4isdhc.com cards do this which are dstt(i) clones not r4)