@le2064 I dont know about you, but I have my roms, saves and bios on a NAS server on my Network.
And I have 2 rasppi3+ on my home, both sharing roms, saves and bios (I can play on the living room, save and continue on the bedroom).

You have to edit recalbox-boot.conf (as you said before) and add:

case = none: 1
sharedevice=NETWORK
sharenetwork_smb1=ROMS@YOUR_NAS_IP:YOUR_LOGICAL_DRIVE_NAME/recalbox/roms:username=recalbox,password=recalbox,vers=1.0
sharenetwork_smb2=SAVES@YOUR_NAS_IP:YOUR_LOGICAL_DRIVE_NAME/recalbox/saves:username=recalbox,password=recalbox,vers=1.0
sharenetwork_smb3=BIOS@YOUR_NAS_IP:YOUR_LOGICAL_DRIVE_NAME/recalbox/bios:username=recalbox,password=recalbox,vers=1.0

For you to understand, mine is:

sharedevice=NETWORK
sharenetwork_smb1=ROMS@192.168.86.88:Volume_1/recalbox/roms:username=recalbox,password=recalbox,vers=1.0
sharenetwork_smb2=SAVES@192.168.86.88:Volume_1/recalbox/saves:username=recalbox,password=recalbox,vers=1.0
sharenetwork_smb3=BIOS@192.168.86.88:Volume_1/recalbox/bios:username=recalbox,password=recalbox,vers=1.0