diff --git a/functions/configuration.sh b/functions/configuration.sh
index 85873bdcd..b74ea0e50 100755
--- a/functions/configuration.sh
+++ b/functions/configuration.sh
@@ -287,24 +287,33 @@ Prepare_config ()
 			;;
 	esac
 
-	if [ -z "${LB_BOOTLOADERS}" ]
-	then
-		case "${LB_ARCHITECTURE}" in
-			amd64|i386)
-				case "${LB_IMAGE_TYPE}" in
-					hdd|netboot)
-						LB_BOOTLOADERS="syslinux"
-						;;
-					*)
-						LB_BOOTLOADERS="syslinux,grub-efi"
-						;;
-				esac
-				;;
-		esac
+	case "${LB_ARCHITECTURE}" in
+		amd64|i386)
+			LB_BOOTLOADER_BIOS="${LB_BOOTLOADER_BIOS:-syslinux}"
+			if ! In_list "${LB_IMAGE_TYPE}" hdd netboot; then
+				LB_BOOTLOADER_EFI="${LB_BOOTLOADER_EFI:-grub-efi}"
+			fi
+			;;
+	esac
+	# Command line option combines BIOS and EFI selection in one.
+	# Also, need to support old config files that held `LB_BOOTLOADERS`.
+	# Note that this function does not perform validation, so none is done here.
+	if [ -n "${LB_BOOTLOADERS}" ]; then
+		LB_BOOTLOADERS="$(echo "${LB_BOOTLOADERS}" | tr "," " ")"
+		unset LB_BOOTLOADER_BIOS
+		unset LB_BOOTLOADER_EFI
+		local BOOTLOADER
+		for BOOTLOADER in $LB_BOOTLOADERS; do
+			case "${BOOTLOADER}" in
+				grub-legacy|grub-pc|syslinux)
+					LB_BOOTLOADER_BIOS="${BOOTLOADER}"
+					;;
+				grub-efi)
+					LB_BOOTLOADER_EFI="${BOOTLOADER}"
+					;;
+			esac
+		done
 	fi
-	LB_BOOTLOADERS="$(echo "${LB_BOOTLOADERS}" | tr "," " ")"
-
-	LB_FIRST_BOOTLOADER=$(echo "${LB_BOOTLOADERS}" | awk '{ print $1 }')
 
 	LB_CHECKSUMS="${LB_CHECKSUMS:-sha256}"
 
@@ -572,9 +581,18 @@ Validate_config_permitted_values ()
 		exit 1
 	fi
 
-	if [ -z "${LB_BOOTLOADERS}" ]; then
+	if [ -z "${LB_BOOTLOADER_BIOS}" ] && [ -z "${LB_BOOTLOADER_EFI}" ]; then
 		Echo_warning "You have specified no bootloaders; I predict that you will experience some problems!"
-	else
+	fi
+	if [ -n "${LB_BOOTLOADER_BIOS}" ] && ! In_list "${LB_BOOTLOADER_BIOS}" grub-legacy grub-pc syslinux; then
+		Echo_error "You have specified an invalid BIOS bootloader."
+		exit 1
+	fi
+	if [ -n "${LB_BOOTLOADER_EFI}" ] && ! In_list "${LB_BOOTLOADER_EFI}" grub-efi; then
+		Echo_error "You have specified an invalid EFI bootloader."
+		exit 1
+	fi
+	if [ -n "${LB_BOOTLOADERS}" ]; then
 		local BOOTLOADER
 		local BOOTLOADERS_BIOS=0
 		local BOOTLOADERS_EFI=0
diff --git a/scripts/build/binary_grub-efi b/scripts/build/binary_grub-efi
index 2fec81d63..2ee26f40d 100755
--- a/scripts/build/binary_grub-efi
+++ b/scripts/build/binary_grub-efi
@@ -21,7 +21,7 @@ USAGE="${PROGRAM} [--force]"
 # Processing arguments and configuration files
 Init_config_data "${@}"
 
-if ! In_list "grub-efi" $LB_BOOTLOADERS; then
+if [ "${LB_BOOTLOADER_EFI}" != "grub-efi" ]; then
 	exit 0
 fi
 
diff --git a/scripts/build/binary_grub-legacy b/scripts/build/binary_grub-legacy
index 6399b8e5f..4acbd2e50 100755
--- a/scripts/build/binary_grub-legacy
+++ b/scripts/build/binary_grub-legacy
@@ -21,7 +21,7 @@ USAGE="${PROGRAM} [--force]"
 # Processing arguments and configuration files
 Init_config_data "${@}"
 
-if ! In_list "grub-legacy" $LB_BOOTLOADERS; then
+if [ "${LB_BOOTLOADER_BIOS}" != "grub-legacy" ]; then
 	exit 0
 fi
 
diff --git a/scripts/build/binary_grub-pc b/scripts/build/binary_grub-pc
index ac6fd04a1..f639b1aa1 100755
--- a/scripts/build/binary_grub-pc
+++ b/scripts/build/binary_grub-pc
@@ -21,7 +21,7 @@ USAGE="${PROGRAM} [--force]"
 # Processing arguments and configuration files
 Init_config_data "${@}"
 
-if ! In_list "grub-pc" $LB_BOOTLOADERS; then
+if [ "${LB_BOOTLOADER_BIOS}" != "grub-pc" ]; then
 	exit 0
 fi
 
diff --git a/scripts/build/binary_hdd b/scripts/build/binary_hdd
index beaff873d..c6aeedb15 100755
--- a/scripts/build/binary_hdd
+++ b/scripts/build/binary_hdd
@@ -52,15 +52,11 @@ Check_package chroot /sbin/parted parted
 Check_package host /sbin/fdisk fdisk
 Check_package host /sbin/losetup mount
 
-for BOOTLOADER in ${LB_BOOTLOADERS}; do
-	case "${BOOTLOADER}" in
-		grub-legacy)
-			Check_package chroot /usr/sbin/grub grub
-			;;
-	esac
-done
+case "${LB_BOOTLOADER_BIOS}" in
+	grub-legacy)
+		Check_package chroot /usr/sbin/grub grub
+		;;
 
-case ${LB_FIRST_BOOTLOADER} in
 	syslinux)
 		case ${LB_BINARY_FILESYSTEM} in
 			fat*|ntfs)
@@ -189,8 +185,7 @@ case "${LB_BUILD_WITH_CHROOT}" in
 		Chroot chroot "parted -s ${FREELO} set 1 boot on" || true
 		Chroot chroot "parted -s ${FREELO} set 1 lba off" || true
 
-		if [ "${LB_FIRST_BOOTLOADER}" = "syslinux" ]
-		then
+		if [ "${LB_BOOTLOADER_BIOS}" = "syslinux" ]; then
 			dd if=chroot/usr/lib/$(echo ${_BOOTLOADER} | tr [a-z] [A-Z])/mbr.bin of=${FREELO} bs=440 count=1
 		fi
 		;;
@@ -209,8 +204,7 @@ case "${LB_BUILD_WITH_CHROOT}" in
 		parted -s "${FREELO}" set 1 boot on || true
 		parted -s "${FREELO}" set 1 lba off || true
 
-		if [ "${LB_FIRST_BOOTLOADER}" = "syslinux" ]
-		then
+		if [ "${LB_BOOTLOADER_BIOS}" = "syslinux" ]; then
 			dd if=/usr/lib/$(echo ${_BOOTLOADER} | tr [a-z] [A-Z])/mbr.bin of=${FREELO} bs=440 count=1
 		fi
 		;;
@@ -275,8 +269,7 @@ cp -T ${CP_OPTIONS} binary/ chroot/binary.tmp
 
 FIXME()
 {
-if [ "${LB_FIRST_BOOTLOADER}" = "grub-legacy" ]
-then
+if [ "${LB_BOOTLOADER_BIOS}" = "grub-legacy" ]; then
 
 cat > chroot/grub.sh << EOF
 #!/bin/sh
diff --git a/scripts/build/binary_syslinux b/scripts/build/binary_syslinux
index 2374d5c55..d4f4bf272 100755
--- a/scripts/build/binary_syslinux
+++ b/scripts/build/binary_syslinux
@@ -21,7 +21,7 @@ USAGE="${PROGRAM} [--force]"
 # Processing arguments and configuration files
 Init_config_data "${@}"
 
-if ! In_list "syslinux" $LB_BOOTLOADERS; then
+if [ "${LB_BOOTLOADER_BIOS}" != "syslinux" ]; then
 	exit 0
 fi
 
diff --git a/scripts/build/config b/scripts/build/config
index f8fd5ff89..2bd929bc1 100755
--- a/scripts/build/config
+++ b/scripts/build/config
@@ -364,6 +364,7 @@ Local_arguments ()
 				;;
 
 			--bootloaders|--bootloader)
+				# This will be split up into BIOS and EFI selections by `Prepare_config()`
 				LB_BOOTLOADERS="${2}"
 				shift 2
 				;;
@@ -1182,8 +1183,11 @@ LB_BOOTAPPEND_INSTALL="${LB_BOOTAPPEND_INSTALL}"
 # Set boot parameters
 LB_BOOTAPPEND_LIVE_FAILSAFE="${LB_BOOTAPPEND_LIVE_FAILSAFE}"
 
-# Set bootloaders
-LB_BOOTLOADERS="${LB_BOOTLOADERS}"
+# Set BIOS bootloader
+LB_BOOTLOADER_BIOS="${LB_BOOTLOADER_BIOS}"
+
+# Set EFI bootloader
+LB_BOOTLOADER_EFI="${LB_BOOTLOADER_EFI}"
 
 # Set checksums
 LB_CHECKSUMS="${LB_CHECKSUMS}"
diff --git a/scripts/build/source_debian b/scripts/build/source_debian
index 2eed78861..ade03add9 100755
--- a/scripts/build/source_debian
+++ b/scripts/build/source_debian
@@ -54,9 +54,12 @@ Chroot chroot "sh source-selection.sh"
 rm -f chroot/source-selection.sh
 mv chroot/source-selection.txt ./
 
-for BOOTLOADER in ${LB_BOOTLOADERS}; do
-	echo "${BOOTLOADER}" >> source-selection.txt
-done
+if [ -n "${LB_BOOTLOADER_BIOS}" ]; then
+	echo "${LB_BOOTLOADER_BIOS}" >> source-selection.txt
+fi
+if [ -n "${LB_BOOTLOADER_EFI}" ]; then
+	echo "${LB_BOOTLOADER_EFI}" >> source-selection.txt
+fi
 
 echo "live-build" >> source-selection.txt