Thank you for your answers.
I could also play directly from sd-card to get my save on the sd-card, but it's really too slow.
I already tried patching then burning the ROM directly, but I used the patcher from DSLazy. I'll try again this evening with those you advised me.
Does the patcher from DSLazy sometimes work with neomax ?
Important question : If I use this method (patching and flashing directly), will the game work with a 0.5 menu on the flash card ?
Finally, I'm glad to learn menu 0.6 could come with more compatibility.