Ja som si tiez myslel, ze nie, ale asi ano
Creating Multiple Disk Partitions
To create multiple GPT partitions, format the drive without a partition table and then add partitions manually:
[admin@MikroTik] > /disk/format usb1 file-system=ext4 label=usb-flash mbr-partition-table=no
[admin@MikroTik] > /disk/add type=partition parent=usb1 partition-size=200M
[admin@MikroTik] > /disk/add type=partition parent=usb1 partition-size=500M
[admin@MikroTik] > /disk/add type=partition parent=usb1 slot=usb1-last-partition