diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 410704c2f..097f13a02 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -162,7 +162,9 @@ jobs:
         fi
 
         if [[ $(du -s buildroot-ccache | awk -F' ' '{ print $1 }') -gt 4 ]]; then
-          tar -cf - buildroot-ccache | xz -9 -T0 > ccache.tar.xz
+          # Ignore character device files, which are used as "whiteouts" in overlayfs
+          find buildroot-ccache -type f -not -type c -print0 | \
+            tar --null -cf - -T - | xz -9 -T0 > ccache.tar.xz
         fi
 
     - name: Upload build directory
diff --git a/overlays/keystone/configs/riscv32_cva6_defconfig b/overlays/keystone/configs/riscv32_cva6_defconfig
index fe591c128..adfbf74e3 100644
--- a/overlays/keystone/configs/riscv32_cva6_defconfig
+++ b/overlays/keystone/configs/riscv32_cva6_defconfig
@@ -7,6 +7,7 @@ BR2_PACKAGE_HOST_GDB=y
 BR2_PACKAGE_HOST_GDB_TUI=y
 BR2_PACKAGE_HOST_GDB_PYTHON3=y
 BR2_CCACHE=y
+BR2_CCACHE_INITIAL_SETUP="-M0 -F0"
 BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_KEYSTONE_PATH)/patches $(BR2_EXTERNAL_KEYSTONE_PATH)/board/cva6/patches"
 BR2_PER_PACKAGE_DIRECTORIES=y
 BR2_SSP_NONE=y
diff --git a/overlays/keystone/configs/riscv32_generic_defconfig b/overlays/keystone/configs/riscv32_generic_defconfig
index d1a6325fb..6847b4a22 100644
--- a/overlays/keystone/configs/riscv32_generic_defconfig
+++ b/overlays/keystone/configs/riscv32_generic_defconfig
@@ -5,6 +5,7 @@ BR2_PACKAGE_HOST_GDB=y
 BR2_PACKAGE_HOST_GDB_TUI=y
 BR2_PACKAGE_HOST_GDB_PYTHON3=y
 BR2_CCACHE=y
+BR2_CCACHE_INITIAL_SETUP="-M0 -F0"
 BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_KEYSTONE_PATH)/patches"
 BR2_PER_PACKAGE_DIRECTORIES=y
 BR2_SSP_NONE=y
diff --git a/overlays/keystone/configs/riscv64_cva6_defconfig b/overlays/keystone/configs/riscv64_cva6_defconfig
index cbea16b7a..44758e4ea 100644
--- a/overlays/keystone/configs/riscv64_cva6_defconfig
+++ b/overlays/keystone/configs/riscv64_cva6_defconfig
@@ -4,6 +4,7 @@ BR2_PACKAGE_HOST_GDB=y
 BR2_PACKAGE_HOST_GDB_TUI=y
 BR2_PACKAGE_HOST_GDB_PYTHON3=y
 BR2_CCACHE=y
+BR2_CCACHE_INITIAL_SETUP="-M0 -F0"
 BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_KEYSTONE_PATH)/patches $(BR2_EXTERNAL_KEYSTONE_PATH)/board/cva6/patches"
 BR2_PER_PACKAGE_DIRECTORIES=y
 BR2_SSP_NONE=y
diff --git a/overlays/keystone/configs/riscv64_generic_defconfig b/overlays/keystone/configs/riscv64_generic_defconfig
index 4ccf9a9c3..89e02f35b 100644
--- a/overlays/keystone/configs/riscv64_generic_defconfig
+++ b/overlays/keystone/configs/riscv64_generic_defconfig
@@ -5,6 +5,7 @@ BR2_PACKAGE_HOST_GDB=y
 BR2_PACKAGE_HOST_GDB_TUI=y
 BR2_PACKAGE_HOST_GDB_PYTHON3=y
 BR2_CCACHE=y
+BR2_CCACHE_INITIAL_SETUP="-M0 -F0"
 BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_KEYSTONE_PATH)/patches"
 BR2_PER_PACKAGE_DIRECTORIES=y
 BR2_SSP_NONE=y
diff --git a/overlays/keystone/configs/riscv64_hifive_unmatched_defconfig b/overlays/keystone/configs/riscv64_hifive_unmatched_defconfig
index b7547e5fd..8883a9e00 100644
--- a/overlays/keystone/configs/riscv64_hifive_unmatched_defconfig
+++ b/overlays/keystone/configs/riscv64_hifive_unmatched_defconfig
@@ -1,6 +1,7 @@
 BR2_riscv=y
 BR2_TOOLCHAIN_BUILDROOT_CXX=y
 BR2_CCACHE=y
+BR2_CCACHE_INITIAL_SETUP="-M0 -F0"
 BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_KEYSTONE_PATH)/patches $(BR2_EXTERNAL_KEYSTONE_PATH)/board/sifive/hifive-unmatched/patches"
 BR2_PER_PACKAGE_DIRECTORIES=y
 BR2_SSP_NONE=y
diff --git a/overlays/keystone/configs/riscv64_mpfs_defconfig b/overlays/keystone/configs/riscv64_mpfs_defconfig
index 9fd1084e3..91c63309d 100644
--- a/overlays/keystone/configs/riscv64_mpfs_defconfig
+++ b/overlays/keystone/configs/riscv64_mpfs_defconfig
@@ -13,6 +13,7 @@ BR2_TOOLCHAIN_BUILDROOT_CXX=y
 BR2_PACKAGE_HOST_GDB=y
 BR2_PACKAGE_HOST_GDB_PYTHON3=y
 BR2_CCACHE=y
+BR2_CCACHE_INITIAL_SETUP="-M0 -F0"
 BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_KEYSTONE_PATH)/patches $(BR2_EXTERNAL_KEYSTONE_PATH)/board/mpfs/patches"
 BR2_PER_PACKAGE_DIRECTORIES=y
 BR2_SSP_NONE=y