Not quite sure I understand, but I actually think I meant the opposite. Can an emuNAND dump be flashed back to SysNand or will it cause a brick?
Not contradicting you—if I knew the answer I wouldn't have asked the question—but this reasoning doesn't make a lot of sense. All of Gateway's features work perfectly find under SysNand if you boot into Gateway mode without an EmuNand SD card inserted. I installed SaveDataFiler to my SysNand at one point because I wanted to transfer an eShop save and was too lazy to set up EmuNand—yes, this was probably stupid, but it worked perfectly fine.