diff --git a/meta-yocto-bsp/conf/layer.conf b/meta-yocto-bsp/conf/layer.conf
index 49fb135094..18544bd0cf 100644
--- a/meta-yocto-bsp/conf/layer.conf
+++ b/meta-yocto-bsp/conf/layer.conf
@@ -1,11 +1,11 @@
 # We have a conf and classes directory, add to BBPATH
-BBPATH := "${BBPATH}:${LAYERDIR}"
+BBPATH .= ":${LAYERDIR}"
 
 # We have a packages directory, add to BBFILES
-BBFILES := "${BBFILES} ${LAYERDIR}/recipes-*/*/*.bb \
+BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
             ${LAYERDIR}/recipes-*/*/*.bbappend"
 
 BBFILE_COLLECTIONS += "yoctobsp"
-BBFILE_PATTERN_yoctobsp := "^${LAYERDIR}/"
+BBFILE_PATTERN_yoctobsp = "^${LAYERDIR}/"
 BBFILE_PRIORITY_yoctobsp = "5"
 
diff --git a/meta-yocto/conf/layer.conf b/meta-yocto/conf/layer.conf
index 791796243f..89ed171003 100644
--- a/meta-yocto/conf/layer.conf
+++ b/meta-yocto/conf/layer.conf
@@ -1,11 +1,11 @@
 # We have a conf and classes directory, add to BBPATH
-BBPATH := "${LAYERDIR}:${BBPATH}"
+BBPATH =. "${LAYERDIR}:"
 
 # We have a packages directory, add to BBFILES
-BBFILES := "${BBFILES} ${LAYERDIR}/recipes-*/*/*.bb \
+BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
             ${LAYERDIR}/recipes-*/*/*.bbappend"
 
 BBFILE_COLLECTIONS += "yocto"
-BBFILE_PATTERN_yocto := "^${LAYERDIR}/"
+BBFILE_PATTERN_yocto = "^${LAYERDIR}/"
 BBFILE_PRIORITY_yocto = "5"
 
diff --git a/scripts/lib/bsp/substrate/target/arch/common/conf/layer.conf b/scripts/lib/bsp/substrate/target/arch/common/conf/layer.conf
index 921d976dce..97029dd7e4 100644
--- a/scripts/lib/bsp/substrate/target/arch/common/conf/layer.conf
+++ b/scripts/lib/bsp/substrate/target/arch/common/conf/layer.conf
@@ -1,10 +1,10 @@
 # We have a conf and classes directory, add to BBPATH
-BBPATH := "${BBPATH}:${LAYERDIR}"
+BBPATH .= ":${LAYERDIR}"
 
 # We have a recipes directory, add to BBFILES
-BBFILES := "${BBFILES} ${LAYERDIR}/recipes-*/*/*.bb \
+BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
 	${LAYERDIR}/recipes-*/*/*.bbappend"
 
 BBFILE_COLLECTIONS += "{{=machine}}"
-BBFILE_PATTERN_{{=machine}} := "^${LAYERDIR}/"
+BBFILE_PATTERN_{{=machine}} = "^${LAYERDIR}/"
 BBFILE_PRIORITY_{{=machine}} = "6"
diff --git a/scripts/lib/bsp/substrate/target/arch/layer/conf/layer.conf b/scripts/lib/bsp/substrate/target/arch/layer/conf/layer.conf
index 84a9abb1d0..76153f3f8f 100644
--- a/scripts/lib/bsp/substrate/target/arch/layer/conf/layer.conf
+++ b/scripts/lib/bsp/substrate/target/arch/layer/conf/layer.conf
@@ -1,10 +1,10 @@
 # We have a conf and classes directory, add to BBPATH
-BBPATH := "${BBPATH}:${LAYERDIR}"
+BBPATH .= ":${LAYERDIR}"
 
 # We have a recipes directory, add to BBFILES
-BBFILES := "${BBFILES} ${LAYERDIR}/recipes-*/*/*.bb \
+BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
 	${LAYERDIR}/recipes-*/*/*.bbappend"
 
 BBFILE_COLLECTIONS += "{{=layer_name}}"
-BBFILE_PATTERN_{{=layer_name}} := "^${LAYERDIR}/"
+BBFILE_PATTERN_{{=layer_name}} = "^${LAYERDIR}/"
 BBFILE_PRIORITY_{{=layer_name}} = "{{=layer_priority}}"