nanobsd: Expose do_image_prep on command line

do_image_prep will skip the customizations and other image prep that's
the same each time. It was just set before for -I. Expose it now with -p
which doesn't have the other side effects. Also, fix a bug where early
customization was run in this case. We don't want that run multiple
times when building an image from an existing tree or when skipping
image prep (there's no reason to make it a separate hook). Also change
example small media from Compact Flash to SD Card (though maybe it
should be microSD card, eMMC or similar, but that's getting too
verbose).

Sponsored by:		Netflix

share/man/man8/nanobsd.8

@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd July 14, 2025
+.Dd September 9, 2025
 .Dt NANOBSD 8
 .Os
 .Sh NAME
@@ -33,7 +33,7 @@
 .Nd create an embedded FreeBSD system image
 .Sh SYNOPSIS
 .Nm
-.Op Fl BbfhIiKknqvWwX
+.Op Fl BbfhIiKknpqvWwX
 .Op Fl c Ar config-file
 .Sh DESCRIPTION
 The
@@ -42,7 +42,7 @@ utility is a script which produces a minimal implementation of
 .Fx
 (called
 .Nm NanoBSD ) ,
-which typically fits on a small media such as a Compact Flash card,
+which typically fits on a small media such as an SD card,
 or other mass storage medium.
 It can be used to build specialized install images, designed for easy
 installation and maintenance.
@@ -77,6 +77,10 @@ This suppresses the normal cleanup work done before the
 .Cm buildworld
 stage and adds -DNO_CLEAN to the make command line
 used for each build stage (world and kernel).
+.It Fl r
+Don't prepare the image.
+Skip running of the customization and early customization scripts for
+incremental image refinement from world, kernel, or packages.
 .It Fl q
 Make output more quiet.
 .It Fl v

tools/tools/nanobsd/nanobsd.sh

@@ -49,7 +49,7 @@ do_prep_image=true
 . "${topdir}/legacy.sh"
 
 set +e
-args=`getopt BKXWbc:fhiIknqvw $*`
+args=`getopt BKXWbc:fhiIknpqvw $*`
 if [ $? -ne 0 ] ; then
 	usage
 	exit 2
@@ -121,6 +121,10 @@ do
 		do_clean=false
 		shift
 		;;
+	-p)
+		do_prep_image=false
+		shift
+		;;
 	-q)
 		PPLEVEL=$(($PPLEVEL - 1))
 		shift
@@ -158,7 +162,11 @@ fi
 
 pprint 1 "NanoBSD image ${NANO_NAME} build starting"
 
-run_early_customize
+if $do_prep_image ; then
+	run_early_customize
+else
+	pprint 2 "Skipping early customization for image prep (as instructed)"
+fi
 
 if $do_world ; then
 	if $do_clean ; then