It has absolutely nothing to do with backslashes otherwise CFW or Stock wouldn't boot so I have no idea what that other guy is talking about. Try changing the sector in your emummc.ini file to 0X03CBB000. It worked for another person in this
thread.
The whole point of emuMMC is to be on a different firmware than sysMMC in the first place. Them being on the same firmware almost defeats the purpose of emuMMC. Unfortunately, there is no workaround to make games work on whatever firmware you want because of the SDK they are built with which are hard-coded to whatever firmware they correspond with. If the issue truly is your firmware, then that is something that should be brought up with to the Atmosphere team and SciresM because Atmosphere as well as emuMMC is meant to be supported on all firmware versions.