So, I have managed to do it myself, these are the steps (for an MBR dirk):
First of all, you need to change the UUIDs of the inner, encrypted filesystems, per partition.
/dev/sdX# using VeraCrypt and don't mount it, you'll get a device named
blkid to find the UUID of `/dev/mapper/veracrypt1'
/dev/mapper/veracrypt1 with a hex editor (e.g.
hexedit) and replace bytes that represent your UUID (they are in reverse order, due to endianness).
Close the mapper device from VeraCrypt.
Repeat 1-4 for any subsequent encrypted partitions.
Now you want to change the PARTUUID of an MBR disk. It's generated basing on the MBR of the drive itself.
blkid to find the PARTUUID of the drive you want to modify (
/dev/sdX with a hex editor (e.g.
Search for the PARTUUID you found before, without the "-" character and anything after that. It's also in reverse order, due to endianness.
Modify the PARTUUID (which is actually the disk's MBR identifier) how you see fit.
That's all, just make sure not to screw anything up.