The check on the mibsolution files is whether there is any code below the four signature lines you see on the meta files. The unit can only be fooled to read non signed input by putting code after the four line sla1 signature (was a design fault that was exploited).
The AIO files (all in one) you will find that technique is used to get the modified firmware into the unit. Kosher software doesn't have anything after the four line signature of the meta files signature in each
directory. The technique of running code after the signature is the only technique to modify these files to get them in.
If you do open these files up don't save the file else it may add characters and the encryption signature check will fail even on original firmware.