我尝试制作一个可启动的 USB 密钥，并按照此链接中的说明进行操作：如何创建仅 UEFI 可启动的 USB 实时媒体？
我跑：
7z x ubuntu-16.04.3-desktop-amd64.iso -o/media/user1/OCZ/
然后 ：
parted /dev/sdb set 1 boot on
我收到此错误：
Error: The flag 'boot' is not available for loop disk labels.
输出fdisk -l：
Disk /dev/sda: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: F6FA152A-2CAD-4D85-A562-2D4A92A4968F
Device Start End Sectors Size Type
/dev/sda1 2048 1050623 1048576 512M EFI System
/dev/sda2 1050624 944409998 943359375 449.8G Linux filesystem
/dev/sda3 944410624 976771071 32360448 15.4G Linux swap
Disk /dev/sdb: 30.1 GiB, 32326631424 bytes, 63137952 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000
我该如何修复它？