I have no idea what you are talking about, m8...
H7 is booting from its internal flash, not from USB device or SATA HDD. No need for special multiboot plugins!
Once you install an image from a USB stick I suggest you keep it in but initialise (=format) it. You put picons, EPG etc. on it.
SATA HDD/SSD should only handle recording, timeshift and .kodi folder made by default by Kodi plugin.
No such USB or SATA connected device has ever interfered with my H7 booting process - ever!
Read more in PurE2 section in how to structure PurE2 image, written by me...