diff --git a/build/jam/BuildSetup b/build/jam/BuildSetup
index 43b48e69f7..040d84dc34 100644
--- a/build/jam/BuildSetup
+++ b/build/jam/BuildSetup
@@ -27,6 +27,22 @@ if $(JAM_TARGETS) {
 	} else if $(JAM_TARGETS[1]) = run && $(JAM_TARGETS[2]) {
 		local run = [ RunCommandLine $(JAM_TARGETS[2-]) ] ;
 		JAM_TARGETS = $(run) ;
+
+	# "update-image", "update-vmware-image", and "update-install" targets allow
+	# for updating only specific targets in the image/installation dir.
+	} else if $(JAM_TARGETS[1]) = update-image
+		|| $(JAM_TARGETS[1]) = update-vmware-image
+		|| $(JAM_TARGETS[1]) = update-install {
+		HAIKU_IMAGE_UPDATE_ONLY = 1 ;
+		HAIKU_INCLUDE_IN_IMAGE on $(JAM_TARGETS[2-]) = 1 ;
+
+		if $(JAM_TARGETS[1]) = update-image {
+			JAM_TARGETS = haiku-image ;
+		} else if $(JAM_TARGETS[1]) = update-vmware-image {
+			JAM_TARGETS = haiku-vmware-image ;
+		} else {
+			JAM_TARGETS = install-haiku ;
+		}
 	}
 }
 
diff --git a/build/jam/HaikuImage b/build/jam/HaikuImage
index b7ba670820..e6a33a1abe 100644
--- a/build/jam/HaikuImage
+++ b/build/jam/HaikuImage
@@ -348,6 +348,7 @@ AddVariableToScript $(script) : installDir : $(HAIKU_INSTALL_DIR) ;
 AddVariableToScript $(script) : imageSize : $(HAIKU_IMAGE_SIZE) ;
 AddVariableToScript $(script) : addBuildCompatibilityLibDir
 	: $(HOST_ADD_BUILD_COMPATIBILITY_LIB_DIR) ;
+AddVariableToScript $(script) : updateOnly : $(HAIKU_IMAGE_UPDATE_ONLY) ;
 AddTargetVariableToScript $(script) : bfs_shell : bfsShell ;
 AddTargetVariableToScript $(script) : fs_shell_command : fsShellCommand ;
 AddTargetVariableToScript $(script) : <build>copyattr ;
diff --git a/build/jam/ImageRules b/build/jam/ImageRules
index 342753a00c..84cfdc9844 100644
--- a/build/jam/ImageRules
+++ b/build/jam/ImageRules
@@ -95,10 +95,10 @@ actions AddTargetVariableToScript1
 }
 
 
-rule AddDirectoryToHaikuImage
+rule AddDirectoryToHaikuImage directoryTokens
 {
-	# AddDirectoryToHaikuImage <directory>
-	local directoryTokens = $(1) ;
+	# AddDirectoryToHaikuImage <directoryTokens>
+
 	local directory = [ FDirName $(directoryTokens) ] ;
 	directory = $(directory:G=HaikuImage) ;
 
@@ -120,6 +120,20 @@ rule AddDirectoryToHaikuImage
 	return $(directory) ;
 }
 
+rule FilterImageUpdateTargets targets
+{
+	# FilterImageUpdateTargets targets
+
+	local filteredTargets ;
+	local target ;
+	for target in $(targets) {
+		if [ on $(target) return $(HAIKU_INCLUDE_IN_IMAGE) ] {
+			filteredTargets += $(target) ;
+		}
+	}
+	return $(filteredTargets) ;
+}
+
 rule AddFilesToHaikuImage
 {
 	# AddFilesToHaikuImage <directory> : <targets> [ : dest name ]
@@ -128,6 +142,12 @@ rule AddFilesToHaikuImage
 	local targets = $(2) ;
 	local destName = $(3) ;
 
+	# If the image shall only be updated, we filter out all targets not marked
+	# accordingly.
+	if $(HAIKU_IMAGE_UPDATE_ONLY) {
+		targets = [ FilterImageUpdateTargets $(targets) ] ;
+	}
+
 	# We create a unique dummy target per target to install.
 	local target ;
 	for target in $(targets) {
@@ -146,13 +166,17 @@ rule AddFilesToHaikuImage
 	}
 }
 
-rule AddSymlinkToHaikuImage
+rule AddSymlinkToHaikuImage directoryTokens : linkTarget : linkName
 {
 	# AddSymlinkToHaikuImage <directory> : <link target> [ : <link name> ] ;
 	#
-	local directory = [ AddDirectoryToHaikuImage $(1) ] ;
-	local linkTarget = $(2) ;
-	local linkName = $(3) ;
+
+	# If the image shall only be updated, we don't add any symlinks.
+	if $(HAIKU_IMAGE_UPDATE_ONLY) {
+		return ;
+	}
+
+	local directory = [ AddDirectoryToHaikuImage $(directoryTokens) ] ;
 
 	if ! $(linkName) {
 		local path = [ FReverse [ FSplitPath $(linkTarget) ] ] ;
@@ -164,11 +188,15 @@ rule AddSymlinkToHaikuImage
 	SYMLINKS_TO_INSTALL on $(directory) += $(link) ;
 }
 
-rule AddSourceDirectoryToHaikuImage dirTokens
+rule AddSourceDirectoryToHaikuImage dirTokens : alwaysUpdate
 {
-	# AddSourceDirectoryToHaikuImage <dirTokens> ;
+	# AddSourceDirectoryToHaikuImage <dirTokens> : <alwaysUpdate> ;
 
-	HAIKU_INSTALL_SOURCE_DIRS += [ FDirName $(HAIKU_TOP) $(dirTokens) ] ;
+	# If the image shall only be updated, we update sources only, if explicitely
+	# requested.
+	if ! $(HAIKU_IMAGE_UPDATE_ONLY) || $(alwaysUpdate) {
+		HAIKU_INSTALL_SOURCE_DIRS += [ FDirName $(HAIKU_TOP) $(dirTokens) ] ;
+	}
 }
 
 rule AddDriversToHaikuImage
@@ -182,6 +210,11 @@ rule AddDriversToHaikuImage
 
 	AddFilesToHaikuImage beos system add-ons kernel drivers bin : $(targets) ;
 
+	# If the image shall only be updated, we don't add any symlinks.
+	if $(HAIKU_IMAGE_UPDATE_ONLY) {
+		return ;
+	}
+
 	# get the relative symlink path prefix
 	local linkPrefix = ;
 	for i in $(relativeDirectoryTokens) {
@@ -204,7 +237,8 @@ rule AddDriverRegistrationToHaikuImage
 	local relativeDirectoryTokens = $(1) ;
 	local target = $(2) ;
 	local links = $(3) ;
-	local directoryTokens = beos system add-ons kernel registration $(relativeDirectoryTokens) ;
+	local directoryTokens = beos system add-ons kernel registration
+		$(relativeDirectoryTokens) ;
 
 	# get the relative symlink path prefix
 	local linkPrefix = ;
@@ -214,14 +248,19 @@ rule AddDriverRegistrationToHaikuImage
 	linkPrefix += .. drivers bin ;
 
 	# add the symlink
-	AddSymlinkToHaikuImage $(directoryTokens) : [ FDirName $(linkPrefix) $(target:BS) ] : $(links) ;
+	AddSymlinkToHaikuImage $(directoryTokens)
+		: [ FDirName $(linkPrefix) $(target:BS) ] : $(links) ;
 }
 
-rule AddBootModuleSymlinks
+rule AddBootModuleSymlinks targets
 {
 	# AddBootModuleSymlinks <targets> ;
 	#
-	local targets = $(1) ;
+
+	# If the image shall only be updated, we don't add any symlinks.
+	if $(HAIKU_IMAGE_UPDATE_ONLY) {
+		return ;
+	}
 
 	# add the symlinks
 	local target ;
@@ -267,7 +306,10 @@ rule CreateHaikuImageMakeDirectoriesScript
 	}
 
 	Depends $(scriptBody) : $(dirsToCreate) ;
-	CreateHaikuImageMakeDirectoriesScript1 $(scriptBody) : $(dirsToCreate) ;
+	# If the image shall only be updated, we don't create directories.
+	if $(dirsToCreate) && ! $(HAIKU_IMAGE_UPDATE_ONLY) {
+		CreateHaikuImageMakeDirectoriesScript1 $(scriptBody) : $(dirsToCreate) ;
+	}
 }
 
 actions piecemeal CreateHaikuImageMakeDirectoriesScript1
diff --git a/build/jam/UserBuildConfig.sample b/build/jam/UserBuildConfig.sample
index 5d3339f4d6..661daf8daa 100644
--- a/build/jam/UserBuildConfig.sample
+++ b/build/jam/UserBuildConfig.sample
@@ -35,6 +35,17 @@ HAIKU_VMWARE_IMAGE_NAME	= walter.vmdk ;
 # Install Haiku in directory /Haiku.
 HAIKU_INSTALL_DIR = /Haiku ;
 
+# Affects the haiku-image, haiku-vmware-image, and install-haiku targets. Only
+# targets on which the HAIKU_INCLUDE_IN_IMAGE variable has been set will be
+# updated in the image file/installation directory.
+# The update-image, update-vmware-image, and update-install targets always set
+# this variable, so one likely doesn't ever need to set it manually.
+HAIKU_IMAGE_UPDATE_ONLY = 1 ;
+
+# libbe.so and the kernel will be updated on image updates. Note that this
+# doesn't work for pseudo targets like "kernel".
+HAIKU_INCLUDE_IN_IMAGE on libbe.so kernel_x86 = 1 ;
+
 # Add "crashing_app" to the beos/bin directory of the Haiku image/installation.
 # Note, that this also makes the image depend on the target, i.e. it is
 # automatically updated when the image is built.
@@ -43,9 +54,13 @@ AddFilesToHaikuImage beos bin : crashing_app ;
 # Make a symlink to home/config/bin/crash.
 AddSymlinkToHaikuImage home config bin : /beos/bin/crashing_app : crash ;
 
-# Adds the source directory src/kits/storage (recursively) to the image
-# (as /boot/home/HaikuSources/src/kits/storage).
-AddSourceDirectoryToHaikuImage src kits storage ;
+# Adds the source directories src/kits/storage and src/tests/servers/debug
+# (recursively) to the image (as /boot/home/HaikuSources/src/kits/storage
+# and /boot/home/HaikuSources/src/tests/servers/debug respectively).
+# Note that the second directory will also be copied, if the image will only
+# be updated; the first one won't in that case.
+AddSourceDirectoryToHaikuImage src/kits/storage ;
+AddSourceDirectoryToHaikuImage src/tests/servers/debug : 1 ;
 
 # Specify scripts that shall be run when populating the image/installation
 # directory. The "early" script is run before anything has been copied onto
diff --git a/build/scripts/build_haiku_image b/build/scripts/build_haiku_image
index bbc8ff149a..1c7ab54172 100755
--- a/build/scripts/build_haiku_image
+++ b/build/scripts/build_haiku_image
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-# The first argument is the shell script that initializes the variables.
+# The first argument is the shell script that initializes the variables:
 # sourceDir
 # outputDir
 # tmpDir
@@ -10,6 +10,7 @@
 # imageSize
 # addBuildCompatibilityLibDir
 # sourceDirsToCopy
+# updateOnly
 # 
 # bfsShell
 # copyattr
@@ -53,16 +54,20 @@ fi
 # create the image and mount it
 if [ $isImage ]; then
 	echo
-	echo "Creating image ..."
-	dd if=/dev/zero of=$imagePath bs=1M count=$imageSize
-	$bfsShell --initialize $imagePath Haiku
-	$makebootable $imagePath
+	if [ ! $updateOnly ]; then
+		echo "Creating image ..."
+		dd if=/dev/zero of=$imagePath bs=1M count=$imageSize
+		$bfsShell --initialize $imagePath Haiku
+		$makebootable $imagePath
+	fi
 	$bfsShell -n $imagePath > /dev/null &
 	sleep 1
 fi
 
-$mkindex BEOS:APP_SIG
-	# needed to launch apps via signature
+# create BEOS:APP_SIG index -- needed to launch apps via signature
+if [ ! $updateOnly ]; then
+	$mkindex BEOS:APP_SIG
+fi
 
 echo "Populating image ..."
 while [ $# -gt 0 ]; do
@@ -73,55 +78,58 @@ done
 
 # install MIME database
 # TODO: It should be possible to do that in the build system too.
-mimeDBSource=$sourceDir/src/data/beos_mime
-mimeDBDest=${tPrefix}home/config/settings/beos_mime
 
-echo "Deleting old MIME database ..."
+if [ ! $updateOnly ]; then
+	mimeDBSource=$sourceDir/src/data/beos_mime
+	mimeDBDest=${tPrefix}home/config/settings/beos_mime
 
-$rm -rf $mimeDBDest
-$mkdir -p $mimeDBDest
-mkdir -p $tmpDir
-mimeTmpDir=$tmpDir/mime
-mimeTmpIndex=0
+	echo "Deleting old MIME database ..."
 
-# create tmp dir for the MIME conversion stuff
-mkdir -p $mimeTmpDir
+	$rm -rf $mimeDBDest
+	$mkdir -p $mimeDBDest
+	mkdir -p $tmpDir
+	mimeTmpDir=$tmpDir/mime
+	mimeTmpIndex=0
 
-echo "Installing MIME database ..."
+	# create tmp dir for the MIME conversion stuff
+	mkdir -p $mimeTmpDir
 
-for inSuperFile in $mimeDBSource/*.super; do
-	superType=$(basename $inSuperFile .super)
-	outSuperDir=$mimeDBDest/$superType
+	echo "Installing MIME database ..."
 
-	# compile rdef to rsrc file and the rsrc file to attributes
-	mimeTmpIndex=$(($mimeTmpIndex + 1))
-	tmpFile=$mimeTmpDir/mimedb$$_${mimeTmpIndex}.rsrc
-	tmpFile2=$mimeTmpDir/mimedb$$_${mimeTmpIndex}.mime
-	$rc -o $tmpFile $inSuperFile
-	mkdir -p $tmpFile2
-	$resattr -O -o $tmpFile2 $tmpFile
-	$cp -r ${sPrefix}$tmpFile2 $outSuperDir
+	for inSuperFile in $mimeDBSource/*.super; do
+		superType=$(basename $inSuperFile .super)
+		outSuperDir=$mimeDBDest/$superType
 
-	# iterate through the sub types
-	for inSubFile in $mimeDBSource/$superType/*; do
-		# check, if the type exists
-		if test -f $inSubFile && grep META:TYPE $inSubFile > /dev/null 2>&1 ; then
-			subType=$(basename $inSubFile)
-			outSubFile=$outSuperDir/$subType
+		# compile rdef to rsrc file and the rsrc file to attributes
+		mimeTmpIndex=$(($mimeTmpIndex + 1))
+		tmpFile=$mimeTmpDir/mimedb$$_${mimeTmpIndex}.rsrc
+		tmpFile2=$mimeTmpDir/mimedb$$_${mimeTmpIndex}.mime
+		$rc -o $tmpFile $inSuperFile
+		mkdir -p $tmpFile2
+		$resattr -O -o $tmpFile2 $tmpFile
+		$cp -r ${sPrefix}$tmpFile2 $outSuperDir
 
-			# compile rdef to rsrc file and the rsrc file to attributes
-			mimeTmpIndex=$(($mimeTmpIndex + 1))
-			tmpFile=$mimeTmpDir/mimedb$$_${mimeTmpIndex}.rsrc
-			tmpFile2=$mimeTmpDir/mimedb$$_${mimeTmpIndex}.mime
-			$rc -o $tmpFile $inSubFile
-			$resattr -O -o $tmpFile2 $tmpFile
-			$cp ${sPrefix}$tmpFile2 $outSubFile
-		fi
+		# iterate through the sub types
+		for inSubFile in $mimeDBSource/$superType/*; do
+			# check, if the type exists
+			if test -f $inSubFile && grep META:TYPE $inSubFile > /dev/null 2>&1 ; then
+				subType=$(basename $inSubFile)
+				outSubFile=$outSuperDir/$subType
+
+				# compile rdef to rsrc file and the rsrc file to attributes
+				mimeTmpIndex=$(($mimeTmpIndex + 1))
+				tmpFile=$mimeTmpDir/mimedb$$_${mimeTmpIndex}.rsrc
+				tmpFile2=$mimeTmpDir/mimedb$$_${mimeTmpIndex}.mime
+				$rc -o $tmpFile $inSubFile
+				$resattr -O -o $tmpFile2 $tmpFile
+				$cp ${sPrefix}$tmpFile2 $outSubFile
+			fi
+		done
 	done
-done
 
-# cleanup tmp dir
-rm -rf $mimeTmpDir
+	# cleanup tmp dir
+	rm -rf $mimeTmpDir
+fi	# ! updateOnly
 
 
 # install sources