diff --git a/include/image-commands.mk b/include/image-commands.mk
index e6b526dc56a..8badecf1d63 100644
--- a/include/image-commands.mk
+++ b/include/image-commands.mk
@@ -466,6 +466,10 @@ define Build/fit
 	$(call Build/fit-image,$(1))
 endef
 
+# A slot name from the basename alone collides between two targets that share
+# it in different directories below $(KDIR).
+cache_slot = $(KDIR)/cache/$(subst /,_,$(patsubst $(KDIR)/%,%,$(1)))
+
 define Build/libdeflate-gzip
 	$(STAGING_DIR_HOST)/bin/libdeflate-gzip -f -12 -c $@ $(1) > $@.new
 	@mv $@.new $@
@@ -593,7 +597,8 @@ define Build/lzma
 endef
 
 define Build/lzma-no-dict
-	$(STAGING_DIR_HOST)/bin/lzma e $@ $(1) $@.new
+	$(CACHE_RUN) $(call cache_slot,$@).lzma $@ $@.new \
+		$(STAGING_DIR_HOST)/bin/lzma e $@ $(1) $@.new
 	@mv $@.new $@
 endef
 
diff --git a/include/kernel-defaults.mk b/include/kernel-defaults.mk
index 02a4f9cde64..ffb8a5a3e0b 100644
--- a/include/kernel-defaults.mk
+++ b/include/kernel-defaults.mk
@@ -204,6 +204,11 @@ define Kernel/PrepareConfigPerRootfs
 endef
 
 ifneq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),)
+# $1: Per Device Rootfs ID
+# $2: suffix of the compressed initrd
+Kernel/CacheInitrd = $(CACHE_RUN) $(KERNEL_BUILD_DIR)/cache/initrd$(1).cpio.$(2) \
+	$(KERNEL_BUILD_DIR)/initrd$(1).cpio $(KERNEL_BUILD_DIR)/initrd$(1).cpio.$(2)
+
 # $1: Custom TARGET_DIR. If omitted TARGET_DIR is used.
 # $2: If defined Generate Per Rootfs Kernel Directory and use it
 # For Separate Initramfs, the regular kernel is used as is, as its config
@@ -226,16 +231,21 @@ define Kernel/CompileImage/Initramfs
 				$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_BZIP2), \
 					$(STAGING_DIR_HOST)/bin/bzip2 -9 -c < $(KERNEL_BUILD_DIR)/initrd$(2).cpio > $(KERNEL_BUILD_DIR)/initrd$(2).cpio.bzip2;) \
 				$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_GZIP), \
-					$(STAGING_DIR_HOST)/bin/libdeflate-gzip -n -f -S .gzip -12 $(KERNEL_BUILD_DIR)/initrd$(2).cpio;) \
+					$(call Kernel/CacheInitrd,$(2),gzip) \
+					$(STAGING_DIR_HOST)/bin/libdeflate-gzip -n -k -f -S .gzip -12 $(KERNEL_BUILD_DIR)/initrd$(2).cpio;) \
 				$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZ4), \
+					$(call Kernel/CacheInitrd,$(2),lz4) \
 					$(STAGING_DIR_HOST)/bin/lz4c -l -c1 -fz --favor-decSpeed $(KERNEL_BUILD_DIR)/initrd$(2).cpio $(KERNEL_BUILD_DIR)/initrd$(2).cpio.lz4;) \
 				$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZMA), \
+					$(call Kernel/CacheInitrd,$(2),lzma) \
 					$(STAGING_DIR_HOST)/bin/lzma e -lc1 -lp2 -pb2 $(KERNEL_BUILD_DIR)/initrd$(2).cpio $(KERNEL_BUILD_DIR)/initrd$(2).cpio.lzma;) \
 				$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZO), \
 					$(STAGING_DIR_HOST)/bin/lzop -9 -f $(KERNEL_BUILD_DIR)/initrd$(2).cpio;) \
 				$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_XZ), \
-					$(STAGING_DIR_HOST)/bin/xz -T$(if $(filter 1,$(NPROC)),2,0) -9 -fz --check=crc32 $(KERNEL_BUILD_DIR)/initrd$(2).cpio;) \
+					$(call Kernel/CacheInitrd,$(2),xz) \
+					$(STAGING_DIR_HOST)/bin/xz -T$(if $(filter 1,$(NPROC)),2,0) -9 -fzk --check=crc32 $(KERNEL_BUILD_DIR)/initrd$(2).cpio;) \
 				$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_ZSTD), \
+					$(call Kernel/CacheInitrd,$(2),zstd) \
 					$(STAGING_DIR_HOST)/bin/zstd -T0 -f -o $(KERNEL_BUILD_DIR)/initrd$(2).cpio.zstd $(KERNEL_BUILD_DIR)/initrd$(2).cpio;) \
 			}, gen-cpio$(2));,\
 			$(KERNEL_MAKE) $(if $(2),-C $(LINUX_DIR)$(2)) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all);) \
diff --git a/rules.mk b/rules.mk
index 0fd2ccf5123..adae18b97fc 100644
--- a/rules.mk
+++ b/rules.mk
@@ -319,6 +319,7 @@ TARGET_CC:=$(TARGET_CROSS)gcc
 TARGET_CXX:=$(TARGET_CROSS)g++
 TARGET_LD:=$(TARGET_CROSS)ld.$(TARGET_LINKER)
 KPATCH:=$(SCRIPT_DIR)/patch-kernel.sh
+CACHE_RUN:=$(SCRIPT_DIR)/cache-run.sh
 FILECMD:=$(STAGING_DIR_HOST)/bin/file
 SED:=$(STAGING_DIR_HOST)/bin/sed -i -e
 ESED:=$(STAGING_DIR_HOST)/bin/sed -E -i -e
diff --git a/scripts/cache-run.sh b/scripts/cache-run.sh
new file mode 100755
index 00000000000..9c1cc87815b
--- /dev/null
+++ b/scripts/cache-run.sh
@@ -0,0 +1,55 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Usage: cache-run.sh <slot> <input> <output> <command> [<arg>...]
+#
+# Run a command that creates <output> from <input>. If the content of the
+# input, the command line and the command binary are the same as in the
+# last run for <slot>, copy the stored output instead of running the
+# command again. Only use it for deterministic commands, such as the
+# compression of kernel and initramfs images, which are slow and get the
+# same input on most rebuilds.
+
+[ $# -ge 4 ] || {
+	echo "Usage: $0 <slot> <input> <output> <command> [<arg>...]" >&2
+	exit 1
+}
+[ -n "$MKHASH" ] || {
+	echo "$0: MKHASH is not set" >&2
+	exit 1
+}
+
+slot="$1"
+input="$2"
+output="$3"
+shift 3
+
+[ -f "$input" ] || {
+	echo "$0: $input does not exist" >&2
+	exit 1
+}
+tool="$(command -v "$1")" || {
+	echo "$0: $1 not found" >&2
+	exit 1
+}
+
+input_hash="$("$MKHASH" sha256 "$input")" || exit 1
+tool_hash="$("$MKHASH" sha256 "$tool")" || exit 1
+key="$(printf '%s\n' "$input_hash" "$tool_hash" "$@" | "$MKHASH" sha256)" || exit 1
+
+mkdir -p "$(dirname "$slot")" || exit 1
+
+# Two image recipes can hold the same slot at the same time. Hold a lock over
+# the whole slot, so that a reader never sees a half written pair.
+exec 9>"$slot.lock" || exit 1
+flock 9 || exit 1
+
+if [ -f "$slot.data" ] && [ "$(cat "$slot.key" 2>/dev/null)" = "$key" ]; then
+	cmp -s "$slot.data" "$output" && exit 0
+	exec cp "$slot.data" "$output"
+fi
+
+rm -f "$slot.key"
+"$@" || exit
+cp "$output" "$slot.data.new" && mv -f "$slot.data.new" "$slot.data" &&
+	echo "$key" > "$slot.key"