(OK) 移动硬盘（或 U盘），安装 CentOS-8.iso Fedora-30-1.2.iso，修改内核参数：pci=nomsi,noaer

# ls /opt/iso
CentOS-8-x86_64-1905-dvd1.iso  Fedora-Workstation-Live-x86_64-30-1.2.iso

# fdisk /dev/sdb
设备       启动      起点      末尾      扇区   大小 Id 类型
/dev/sdb1  *         2048  54530047  54528000    26G 83 Linux            # CentOS-8-x86_64-1905-dvd1.iso
/dev/sdb2        61442048 266242047 204800000  97.7G 83 Linux
/dev/sdb3       266242048 625141759 358899712 171.1G  7 HPFS/NTFS/exFAT
/dev/sdb4        54530048  61442047   6912000   3.3G 83 Linux            # Fedora-Workstation-Live-x86_64-30-1.2.iso

# (1) 安装 CentOS-8-x86_64-1905-dvd1.iso

livecd-iso-to-disk --reset-mbr CentOS-8-x86_64-1905-dvd1.iso /dev/sdb1
cp CentOS-8-x86_64-1905-dvd1.iso /run/media/root/centos                # /run/media/root/centos is /dev/sdb1

# 移动硬盘启动 CentOS-8，安装源 选择 CentOS-8-x86_64-1905-dvd1.iso

# (2) 安装 Fedora-Workstation-Live-x86_64-30-1.2.iso

# fdisk /dev/sdb
设备       启动      起点      末尾      扇区   大小 Id 类型
/dev/sdb1  *         2048  54530047  54528000    26G 83 Linux            # CentOS-8-x86_64-1905-dvd1.iso
/dev/sdb4  *     54530048  61442047   6912000   3.3G 83 Linux            # Fedora-Workstation-Live-x86_64-30-1.2.iso

livecd-iso-to-disk Fedora-Workstation-Live-x86_64-30-1.2.iso /dev/sdb4

# fdisk /dev/sdb
设备       启动      起点      末尾      扇区   大小 Id 类型
/dev/sdb1  *         2048  54530047  54528000    26G 83 Linux            # CentOS-8-x86_64-1905-dvd1.iso
/dev/sdb4        54530048  61442047   6912000   3.3G 83 Linux            # Fedora-Workstation-Live-x86_64-30-1.2.iso

# (3) 修改文件 /run/media/root/centos/syslinux/extlinux.conf，内容如下：

label linux
  menu label ^Install CentOS Linux 8.0.1905 (pci=nomsi)
  kernel vmlinuz
  append initrd=initrd.img inst.stage2=hd:UUID=359a70d1-4ea4-7e42-bc49-50b02f0c58b3 quiet pci=nomsi
label linux
  menu label ^Start Fedora-Workstation-Live 30 (pci=nomsi)
  kernel vmlinuz
  append initrd=initrd.img root=live:UUID=dce64d41-a28d-7f4d-aca1-1729314bcdb6  rd.live.image rw quiet pci=nomsi

label linux
  menu label ^Install CentOS Linux 8.0.1905 (pci=noaer)
  kernel vmlinuz
  append initrd=initrd.img inst.stage2=hd:UUID=359a70d1-4ea4-7e42-bc49-50b02f0c58b3 quiet pci=noaer
label linux
  menu label ^Start Fedora-Workstation-Live 30 (pci=noaer)
  kernel vmlinuz
  append initrd=initrd.img root=live:UUID=dce64d41-a28d-7f4d-aca1-1729314bcdb6  rd.live.image rw quiet pci=noaer

label linux
  menu label ^Install CentOS Linux 8.0.1905 (pci=nomsi,noaer)
  kernel vmlinuz
  append initrd=initrd.img inst.stage2=hd:UUID=359a70d1-4ea4-7e42-bc49-50b02f0c58b3 quiet pci=nomsi,noaer
label linux
  menu label ^Start Fedora-Workstation-Live 30 (pci=nomsi,noaer)
  kernel vmlinuz
  append initrd=initrd.img root=live:UUID=dce64d41-a28d-7f4d-aca1-1729314bcdb6  rd.live.image rw quiet pci=nomsi,noaer

# (4) 安装 CentOS-8-x86_64-1905-dvd1.iso

# (5) 安装 Fedora-Workstation-Live-x86_64-30-1.2.iso