diff --git a/packages/linux-firmware/brcmfmac_sdio-firmware-imx/package.mk b/packages/linux-firmware/brcmfmac_sdio-firmware-imx/package.mk
index 6731f6cf36..deaee8596a 100644
--- a/packages/linux-firmware/brcmfmac_sdio-firmware-imx/package.mk
+++ b/packages/linux-firmware/brcmfmac_sdio-firmware-imx/package.mk
@@ -6,14 +6,14 @@ PKG_VERSION="0.1"
 PKG_SHA256="4c8ed8ae39ecd05d7e3aeebc98cf230912cdcc887fa78d5112f981b6f9358b6e"
 PKG_LICENSE="GPL"
 PKG_SITE="https://github.com/LibreELEC/LibreELEC.tv"
-PKG_URL="$DISTRO_SRC/$PKG_NAME-$PKG_VERSION.tar.xz"
+PKG_URL="${DISTRO_SRC}/${PKG_NAME}-${PKG_VERSION}.tar.xz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="Firmware for brcm bluetooth chips used in some Freescale iMX based devices."
 
 makeinstall_target() {
-  mkdir -p $INSTALL/usr/bin
-    cp -av brcm_patchram_plus $INSTALL/usr/bin/
+  mkdir -p ${INSTALL}/usr/bin
+    cp -av brcm_patchram_plus ${INSTALL}/usr/bin/
 
-  mkdir -p $INSTALL/$(get_kernel_overlay_dir)/lib/firmware/
-    cp -av firmware/brcm $INSTALL/$(get_kernel_overlay_dir)/lib/firmware/
+  mkdir -p ${INSTALL}/$(get_kernel_overlay_dir)/lib/firmware/
+    cp -av firmware/brcm ${INSTALL}/$(get_kernel_overlay_dir)/lib/firmware/
 }
diff --git a/packages/linux-firmware/brcmfmac_sdio-firmware-rpi/package.mk b/packages/linux-firmware/brcmfmac_sdio-firmware-rpi/package.mk
index cca381204e..df40e55ec7 100644
--- a/packages/linux-firmware/brcmfmac_sdio-firmware-rpi/package.mk
+++ b/packages/linux-firmware/brcmfmac_sdio-firmware-rpi/package.mk
@@ -7,20 +7,20 @@ PKG_VERSION="c13705adcee0b35824db70b5f035c86a7088dfce"
 PKG_SHA256="7c453641e332d70a310dae8ee450b6ce024ed0a2204da1b3f3a3624191be60d8"
 PKG_LICENSE="GPL"
 PKG_SITE="https://github.com/LibreELEC/LibreELEC.tv"
-PKG_URL="https://github.com/LibreELEC/$PKG_NAME/archive/$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/LibreELEC/${PKG_NAME}/archive/${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="Firmware for brcm bluetooth chips used on RaspberryPi devices."
 PKG_TOOLCHAIN="manual"
 
 makeinstall_target() {
-  DESTDIR=$INSTALL/$(get_kernel_overlay_dir) ./install
+  DESTDIR=${INSTALL}/$(get_kernel_overlay_dir) ./install
 }
 
 post_makeinstall_target() {
   # Install rpi btuart script to bring up Bluetooth
-  mkdir -p $INSTALL/usr/bin
-    cp -P $PKG_DIR/scripts/rpi-btuart $INSTALL/usr/bin
-    cp -P $PKG_DIR/scripts/rpi-udev $INSTALL/usr/bin
+  mkdir -p ${INSTALL}/usr/bin
+    cp -P ${PKG_DIR}/scripts/rpi-btuart ${INSTALL}/usr/bin
+    cp -P ${PKG_DIR}/scripts/rpi-udev ${INSTALL}/usr/bin
 }
 
 post_install() {
diff --git a/packages/linux-firmware/brcmfmac_sdio-firmware/package.mk b/packages/linux-firmware/brcmfmac_sdio-firmware/package.mk
index a8375621b1..8f28cd2c35 100644
--- a/packages/linux-firmware/brcmfmac_sdio-firmware/package.mk
+++ b/packages/linux-firmware/brcmfmac_sdio-firmware/package.mk
@@ -6,14 +6,14 @@ PKG_VERSION="6d49ff1bc15a1c55f711292ed22a7687fa2c9e14"
 PKG_SHA256="f3698b81fec401dc9b20c32896aab884e8dded1b1e7a5e595060fe3cbce7a5d3"
 PKG_LICENSE="GPL"
 PKG_SITE="https://github.com/LibreELEC/brcmfmac_sdio-firmware"
-PKG_URL="https://github.com/LibreELEC/brcmfmac_sdio-firmware/archive/$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/LibreELEC/brcmfmac_sdio-firmware/archive/${PKG_VERSION}.tar.gz"
 PKG_LONGDESC="Broadcom SDIO firmware used with LibreELEC"
 PKG_TOOLCHAIN="manual"
 
 post_makeinstall_target() {
-  FW_TARGET_DIR=$INSTALL/$(get_full_firmware_dir)
+  FW_TARGET_DIR=${INSTALL}/$(get_full_firmware_dir)
 
-  if find_file_path firmwares/$PKG_NAME.dat; then
+  if find_file_path firmwares/${PKG_NAME}.dat; then
     FW_LISTS="${FOUND_PATH}"
   else
     FW_LISTS="${PKG_DIR}/firmwares/any.dat ${PKG_DIR}/firmwares/${TARGET_ARCH}.dat"
@@ -39,8 +39,8 @@ post_makeinstall_target() {
     done < ${fwlist}
   done
 
-  mkdir -p $INSTALL/usr/bin
-    cp $PKG_DIR/scripts/brcmfmac-firmware-setup $INSTALL/usr/bin
+  mkdir -p ${INSTALL}/usr/bin
+    cp ${PKG_DIR}/scripts/brcmfmac-firmware-setup ${INSTALL}/usr/bin
 }
 
 post_install() {
diff --git a/packages/linux-firmware/dvb-firmware/package.mk b/packages/linux-firmware/dvb-firmware/package.mk
index 57c8f0ce34..be65d4f746 100644
--- a/packages/linux-firmware/dvb-firmware/package.mk
+++ b/packages/linux-firmware/dvb-firmware/package.mk
@@ -7,13 +7,13 @@ PKG_VERSION="1.4.0"
 PKG_SHA256="17d6a5727f7728ef618055089eb78372b3af7ed64ff3ed116211258727188ff0"
 PKG_LICENSE="Free-to-use"
 PKG_SITE="https://github.com/LibreELEC/dvb-firmware"
-PKG_URL="https://github.com/LibreELEC/dvb-firmware/archive/$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/LibreELEC/dvb-firmware/archive/${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="dvb-firmware: firmwares for various DVB drivers"
 PKG_TOOLCHAIN="manual"
 
 makeinstall_target() {
-  PKG_FW_DIR="$INSTALL/$(get_kernel_overlay_dir)/lib/firmware"
-  mkdir -p "$PKG_FW_DIR"
-    cp -a "$PKG_BUILD/firmware/"* "$PKG_FW_DIR"
+  PKG_FW_DIR="${INSTALL}/$(get_kernel_overlay_dir)/lib/firmware"
+  mkdir -p "${PKG_FW_DIR}"
+    cp -a "${PKG_BUILD}/firmware/"* "${PKG_FW_DIR}"
 }
diff --git a/packages/linux-firmware/firmware-dragonboard/package.mk b/packages/linux-firmware/firmware-dragonboard/package.mk
index ae83b5f28d..bde17b42ff 100644
--- a/packages/linux-firmware/firmware-dragonboard/package.mk
+++ b/packages/linux-firmware/firmware-dragonboard/package.mk
@@ -13,9 +13,9 @@ PKG_LONGDESC="Additional firmware for Dragonboard 410c"
 PKG_TOOLCHAIN="manual"
 
 unpack() {
-  mkdir -p $PKG_BUILD
-    cd $PKG_BUILD
-    sh $SOURCES/$PKG_NAME/$PKG_NAME-$PKG_VERSION.bin --auto-accept
+  mkdir -p ${PKG_BUILD}
+    cd ${PKG_BUILD}
+    sh ${SOURCES}/${PKG_NAME}/${PKG_NAME}-${PKG_VERSION}.bin --auto-accept
 }
 
 make_target() {
@@ -23,14 +23,14 @@ make_target() {
 }
 
 makeinstall_target() {
-  mkdir -p $INSTALL/$(get_full_firmware_dir)/qcom/venus-1.8/
-    cp -a linux-board-support-package-v${PKG_VERSION%.0}/proprietary-linux/* $INSTALL/$(get_full_firmware_dir)
-    cp -a linux-board-support-package-v${PKG_VERSION%.0}/proprietary-linux/venus* $INSTALL/$(get_full_firmware_dir)/qcom/venus-1.8/
-    rm $INSTALL/$(get_full_firmware_dir)/firmware.tar
+  mkdir -p ${INSTALL}/$(get_full_firmware_dir)/qcom/venus-1.8/
+    cp -a linux-board-support-package-v${PKG_VERSION%.0}/proprietary-linux/* ${INSTALL}/$(get_full_firmware_dir)
+    cp -a linux-board-support-package-v${PKG_VERSION%.0}/proprietary-linux/venus* ${INSTALL}/$(get_full_firmware_dir)/qcom/venus-1.8/
+    rm ${INSTALL}/$(get_full_firmware_dir)/firmware.tar
 
     MTOOLS_SKIP_CHECK=1 mcopy -n -i linux-board-support-package-v${PKG_VERSION%.0}/bootloaders-linux/NON-HLOS.bin \
                                     ::image/modem.* \
                                     ::image/mba.mbn \
                                     ::image/wcnss.* \
-                                    $INSTALL/$(get_full_firmware_dir)
+                                    ${INSTALL}/$(get_full_firmware_dir)
 }
diff --git a/packages/linux-firmware/firmware-imx/package.mk b/packages/linux-firmware/firmware-imx/package.mk
index 90f2bb57ac..226694dc13 100644
--- a/packages/linux-firmware/firmware-imx/package.mk
+++ b/packages/linux-firmware/firmware-imx/package.mk
@@ -14,15 +14,15 @@ PKG_LONGDESC="firmware-imx: Freescale IMX firmware such as for the VPU"
 PKG_TOOLCHAIN="manual"
 
 unpack() {
-  cd $(dirname $PKG_BUILD)
-  sh $SOURCES/$PKG_NAME/$PKG_NAME-$PKG_VERSION.bin --auto-accept
+  cd $(dirname ${PKG_BUILD})
+  sh ${SOURCES}/${PKG_NAME}/${PKG_NAME}-${PKG_VERSION}.bin --auto-accept
 }
 
 makeinstall_target() {
-  mkdir -p $INSTALL/$(get_full_firmware_dir)/imx/sdma
-    cp -P firmware/sdma/sdma-imx6q.bin $INSTALL/$(get_full_firmware_dir)/imx/sdma
+  mkdir -p ${INSTALL}/$(get_full_firmware_dir)/imx/sdma
+    cp -P firmware/sdma/sdma-imx6q.bin ${INSTALL}/$(get_full_firmware_dir)/imx/sdma
 
-  mkdir -p $INSTALL/$(get_full_firmware_dir)/vpu
-    cp -P firmware/vpu/vpu_fw_imx6d.bin $INSTALL/$(get_full_firmware_dir)/vpu
-    cp -P firmware/vpu/vpu_fw_imx6q.bin $INSTALL/$(get_full_firmware_dir)/vpu
+  mkdir -p ${INSTALL}/$(get_full_firmware_dir)/vpu
+    cp -P firmware/vpu/vpu_fw_imx6d.bin ${INSTALL}/$(get_full_firmware_dir)/vpu
+    cp -P firmware/vpu/vpu_fw_imx6q.bin ${INSTALL}/$(get_full_firmware_dir)/vpu
 }
diff --git a/packages/linux-firmware/iwlwifi-firmware/package.mk b/packages/linux-firmware/iwlwifi-firmware/package.mk
index 69a9b24701..1924e57085 100644
--- a/packages/linux-firmware/iwlwifi-firmware/package.mk
+++ b/packages/linux-firmware/iwlwifi-firmware/package.mk
@@ -7,11 +7,11 @@ PKG_VERSION="422508ec618285ef41a6a4baae731cb84b2a53be"
 PKG_SHA256="67f6097c62feb82bd51bd94b8b5607a37bf5cb34ae079649d35e505c2db2b107"
 PKG_LICENSE="Free-to-use"
 PKG_SITE="https://github.com/LibreELEC/iwlwifi-firmware"
-PKG_URL="https://github.com/LibreELEC/iwlwifi-firmware/archive/$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/LibreELEC/iwlwifi-firmware/archive/${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="iwlwifi-firmware: firmwares for various Intel WLAN drivers"
 PKG_TOOLCHAIN="manual"
 
 makeinstall_target() {
-  DESTDIR=$INSTALL/$(get_kernel_overlay_dir) ./install
+  DESTDIR=${INSTALL}/$(get_kernel_overlay_dir) ./install
 }
diff --git a/packages/linux-firmware/kernel-firmware/package.mk b/packages/linux-firmware/kernel-firmware/package.mk
index fb427a3b18..483a9e2a0c 100644
--- a/packages/linux-firmware/kernel-firmware/package.mk
+++ b/packages/linux-firmware/kernel-firmware/package.mk
@@ -6,7 +6,7 @@ PKG_VERSION="20201218"
 PKG_SHA256="d60a418260bc083df8c7d3359aa207b48181ec8354b6c8545cac28ff19ce8950"
 PKG_LICENSE="other"
 PKG_SITE="https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/"
-PKG_URL="https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/snapshot/$PKG_VERSION.tar.gz"
+PKG_URL="https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/snapshot/${PKG_VERSION}.tar.gz"
 PKG_NEED_UNPACK="${PROJECT_DIR}/${PROJECT}/packages/${PKG_NAME} ${PROJECT_DIR}/${PROJECT}/devices/${DEVICE}/packages/${PKG_NAME}"
 PKG_LONGDESC="kernel-firmware: kernel related firmware"
 PKG_TOOLCHAIN="manual"
@@ -25,7 +25,7 @@ post_patch() {
 
 # Install additional miscellaneous drivers
 makeinstall_target() {
-  FW_TARGET_DIR=$INSTALL/$(get_full_firmware_dir)
+  FW_TARGET_DIR=${INSTALL}/$(get_full_firmware_dir)
 
   if find_file_path config/kernel-firmware.dat; then
     FW_LISTS="${FOUND_PATH}"
@@ -67,12 +67,12 @@ makeinstall_target() {
   # They are also not required at all if the kernel is not suitably configured.
   if listcontains "${FIRMWARE}" "brcmfmac_sdio-firmware-rpi" || \
      ! grep -q "^CONFIG_BRCMFMAC_SDIO=y" ${PKG_KERNEL_CFG_FILE}; then
-    rm -fr $FW_TARGET_DIR/brcm/brcmfmac43430*-sdio.*
-    rm -fr $FW_TARGET_DIR/brcm/brcmfmac43455*-sdio.*
+    rm -fr ${FW_TARGET_DIR}/brcm/brcmfmac43430*-sdio.*
+    rm -fr ${FW_TARGET_DIR}/brcm/brcmfmac43455*-sdio.*
   fi
 
   # brcm pcie firmware is only needed by x86_64
-  [ "$TARGET_ARCH" != "x86_64" ] && rm -fr $FW_TARGET_DIR/brcm/*-pcie.*
+  [ "${TARGET_ARCH}" != "x86_64" ] && rm -fr ${FW_TARGET_DIR}/brcm/*-pcie.*
 
   # Cleanup - which may be project or device specific
   find_file_path scripts/cleanup.sh && ${FOUND_PATH} ${FW_TARGET_DIR} || true
diff --git a/packages/linux-firmware/misc-firmware/package.mk b/packages/linux-firmware/misc-firmware/package.mk
index c790f4a0ba..ba9c2964fa 100644
--- a/packages/linux-firmware/misc-firmware/package.mk
+++ b/packages/linux-firmware/misc-firmware/package.mk
@@ -7,11 +7,11 @@ PKG_VERSION="868fb584096c17ddcbc85e472e71f9b8d27da91f"
 PKG_SHA256="862a5a62b9794d7c6753ac0f7ae03fd34ee2564199afd61c42dc8f69d4c5b876"
 PKG_LICENSE="Free-to-use"
 PKG_SITE="https://github.com/LibreELEC/misc-firmware"
-PKG_URL="https://github.com/LibreELEC/misc-firmware/archive/$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/LibreELEC/misc-firmware/archive/${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain kernel-firmware"
 PKG_LONGDESC="misc-firmware: firmwares for various drivers"
 PKG_TOOLCHAIN="manual"
 
 makeinstall_target() {
-  DESTDIR=$INSTALL/$(get_kernel_overlay_dir) ./install
+  DESTDIR=${INSTALL}/$(get_kernel_overlay_dir) ./install
 }
diff --git a/packages/linux-firmware/rtl8723bs_bt/package.mk b/packages/linux-firmware/rtl8723bs_bt/package.mk
index 80f43bfefa..3dda0316df 100644
--- a/packages/linux-firmware/rtl8723bs_bt/package.mk
+++ b/packages/linux-firmware/rtl8723bs_bt/package.mk
@@ -6,6 +6,6 @@ PKG_VERSION="09eb91f52a639ec5e4c5c4c98dc2afede046cf20"
 PKG_SHA256="4bb8483c4a14a9e0dfc4a6ddca18486caab5f361be2441b91e9e2a399ca9f33e"
 PKG_LICENSE="GPL"
 PKG_SITE="https://github.com/lwfinger/rtl8723bs_bt"
-PKG_URL="https://github.com/lwfinger/rtl8723bs_bt/archive/$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/lwfinger/rtl8723bs_bt/archive/${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="rtl8723bs_bt Linux firmware"
diff --git a/packages/linux-firmware/wlan-firmware/package.mk b/packages/linux-firmware/wlan-firmware/package.mk
index d757153bd6..355c2f0457 100644
--- a/packages/linux-firmware/wlan-firmware/package.mk
+++ b/packages/linux-firmware/wlan-firmware/package.mk
@@ -6,11 +6,11 @@ PKG_VERSION="adb069a3c95913f4a55e540ed7bb2be33a582479"
 PKG_SHA256="1cd010f0e9eaba38376c15b08520ea1825fcb84c73bb1b4ce8ce248d6530eccc"
 PKG_LICENSE="Free-to-use"
 PKG_SITE="https://github.com/LibreELEC/wlan-firmware"
-PKG_URL="https://github.com/LibreELEC/wlan-firmware/archive/$PKG_VERSION.tar.gz"
+PKG_URL="https://github.com/LibreELEC/wlan-firmware/archive/${PKG_VERSION}.tar.gz"
 PKG_DEPENDS_TARGET="toolchain"
 PKG_LONGDESC="wlan-firmware: firmwares for various WLAN drivers"
 PKG_TOOLCHAIN="manual"
 
 makeinstall_target() {
-  DESTDIR=$INSTALL/$(get_kernel_overlay_dir) ./install
+  DESTDIR=${INSTALL}/$(get_kernel_overlay_dir) ./install
 }