MFC r293188:
Prevent memstick installation medium from attempting to mount
the root filesystem read-write. This causes problems booting
the memstick installation medium from write-protected USB flash
drives.

PR: 187161, 205886
Sponsored by: The FreeBSD Foundation

MFC UEFI memstick build script

r264935 (gjb):

Add a separate script to build the memstick.img and the
mini-memstick.img with UEFI support.

As the comments in the file suggest, 1) there must
be existing ${.OBJDIR}/usr/src/release/{release,bootonly};
2) TARGET/TARGET_ARCH must be amd64; and 3) it must be
a vt(4)-enabled kernel with vt_efifb (*not* vt_vga).

This script is not hooked into release/Makefile in any way
until further testing is complete.

r264992 (nwhitehorn):

Make a dual-boot BIOS/UEFI memstick image. Testing required before
this gets renamed make-memstick.sh.

r265017 (nwhitehorn):

loader's GPT support on BIOS does not seem to like the root
filesystem being the last filesystem on the disk for some reason
when made by this script. Add a vestigial swap partition to allow
this to boot with QEMU BIOS.

Approved by: re
Sponsored by: The FreeBSD Foundation

MFC UEFI memstick build script

r264935 (gjb):

Add a separate script to build the memstick.img and the
mini-memstick.img with UEFI support.

As the comments in the file suggest, 1) there must
be existing ${.OBJDIR}/usr/src/release/{release,bootonly};
2) TARGET/TARGET_ARCH must be amd64; and 3) it must be
a vt(4)-enabled kernel with vt_efifb (*not* vt_vga).

This script is not hooked into release/Makefile in any way
until further testing is complete.

r264992 (nwhitehorn):

Make a dual-boot BIOS/UEFI memstick image. Testing required before
this gets renamed make-memstick.sh.

r265017 (nwhitehorn):

loader's GPT support on BIOS does not seem to like the root
filesystem being the last filesystem on the disk for some reason
when made by this script. Add a vestigial swap partition to allow
this to boot with QEMU BIOS.

Approved by: re
Sponsored by: The FreeBSD Foundation