Index: release/Makefile.vm
===================================================================
--- release/Makefile.vm
+++ release/Makefile.vm
@@ -7,8 +7,8 @@
 
 VMTARGETS=	vm-image
 VMFORMATS?=	vhd vmdk qcow2 raw
-VMSIZE?=	4096M
-SWAPSIZE?=	1G
+VMSIZE?=	4096m
+SWAPSIZE?=	1g
 VMBASE?=	vm
 
 VHD_DESC=	Azure, VirtualPC, Hyper-V, Xen disk image
@@ -54,7 +54,7 @@
 .if ( ${TARGET_ARCH} != "i386" ) || ( ${MACHINE_ARCH} != "amd64" )
 .if !exists(/usr/local/bin/qemu-${TARGET_ARCH}-static)
 .if exists(${PORTSDIR}/emulators/qemu-user-static/Makefile)
-	env - PATH=$$PATH make -C ${PORTSDIR}/emulators/qemu-user-static BATCH=1 all install clean
+	env - UNAME_r="${REVISION}-${BRANCH}" PATH=$$PATH make -C ${PORTSDIR}/emulators/qemu-user-static BATCH=1 all install clean
 .else
 .if !exists(/usr/local/sbin/pkg-static)
 	env ASSUME_ALWAYS_YES=yes pkg bootstrap -y
Index: release/release.conf.sample
===================================================================
--- release/release.conf.sample
+++ release/release.conf.sample
@@ -106,8 +106,8 @@
 
 ## If WITH_VMIMAGES is set to a non-empty value, this is the size of the
 ## virtual machine disk filesystem.  Valid size values are described in
-## the truncate(1) manual page.
-#VMSIZE="20G"
+## the makefs(8) manual page.
+#VMSIZE="20g"
 
 ## If WITH_VMIMAGES is set to a non-empty value, this is a list of disk
 ## image formats to create.  Valid values are listed in the mkimg(1)
Index: release/tools/basic-ci.conf
===================================================================
--- release/tools/basic-ci.conf
+++ release/tools/basic-ci.conf
@@ -4,7 +4,7 @@
 #
 
 # Should be enough for base image, image can be resized in needed
-export VMSIZE=5G
+export VMSIZE=5g
 
 # Set to a list of third-party software to enable in rc.conf(5).
 export VM_RC_LIST="sshd growfs"
Index: release/tools/ec2.conf
===================================================================
--- release/tools/ec2.conf
+++ release/tools/ec2.conf
@@ -24,7 +24,7 @@
 # Note that if this is set to <N>G, we will end up with an <N+1> GB disk
 # image since VMSIZE is the size of the UFS partition, not the disk which
 # it resides within.
-export VMSIZE=5000M
+export VMSIZE=5000m
 
 # No swap space; the ec2_ephemeralswap rc.d script will allocate swap
 # space on EC2 ephemeral disks.  (If they exist -- the T2 low-cost instances
Index: release/tools/gce.conf
===================================================================
--- release/tools/gce.conf
+++ release/tools/gce.conf
@@ -4,7 +4,7 @@
 #
 
 # The default of 3GB is too small for GCE, so override the size here.
-export VMSIZE=20G
+export VMSIZE=20g
 
 # Set to a list of packages to install.
 export VM_EXTRA_PACKAGES="firstboot-freebsd-update firstboot-pkgs \
Index: release/tools/vagrant.conf
===================================================================
--- release/tools/vagrant.conf
+++ release/tools/vagrant.conf
@@ -4,7 +4,7 @@
 #
 
 # The default of 3GB is too small for Vagrant, so override the size here.
-export VMSIZE=8G
+export VMSIZE=8g
 
 # Packages to install into the image we're creating.  This is a deliberately
 # minimalist set, providing only the packages necessary to bootstrap.
Index: share/man/man7/release.7
===================================================================
--- share/man/man7/release.7
+++ share/man/man7/release.7
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 1, 2020
+.Dd March 4, 2021
 .Dt RELEASE 7
 .Os
 .Sh NAME
@@ -383,9 +383,9 @@
 .It Va VMSIZE
 Set to change the size of the virtual machine disk capacity.
 The default value is
-.Va 20G .
+.Va 20g .
 See
-.Xr truncate 1
+.Xr makefs 8
 for valid values.
 .Pp
 Virtual machine disk images are, by default, created as sparse images.
Index: usr.sbin/bhyve/bhyverun.c
===================================================================
--- usr.sbin/bhyve/bhyverun.c
+++ usr.sbin/bhyve/bhyverun.c
@@ -69,6 +69,7 @@
 #include <sysexits.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <uuid.h>
 #ifdef BHYVE_SNAPSHOT
 #include <ucl.h>
 #include <unistd.h>
@@ -1077,6 +1078,16 @@
 	fbsdrun_addcpu(ctx, BSP, vcpu, rip);
 }
 
+bool 
+is_valid_uuid(const char* uuid_str)
+{
+	uuid_t uuid;
+	uint32_t uuid_status;
+
+	uuid_from_string(uuid_str, &uuid, &uuid_status);
+	return  uuid_status == uuid_s_ok;
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -1196,6 +1207,9 @@
 			rtc_localtime = 0;
 			break;
 		case 'U':
+			if (is_valid_uuid(optarg) == false) {
+				errx(EX_USAGE, "invalid UUID '%s'", optarg);
+			}
 			guest_uuid_str = optarg;
 			break;
 		case 'w':