diff --git a/include/kernel.mk b/include/kernel.mk
index 01b737f132..ffc9ea5260 100644
--- a/include/kernel.mk
+++ b/include/kernel.mk
@@ -101,7 +101,7 @@ endif
 KERNEL_MAKE = $(MAKE) $(KERNEL_MAKEOPTS)
 
 KERNEL_MAKE_FLAGS = \
-	KCFLAGS="$(call iremap,$(BUILD_DIR),$(notdir $(BUILD_DIR)))" \
+	KCFLAGS="$(call iremap,$(BUILD_DIR),$(notdir $(BUILD_DIR))) $(call qstrip,$(CONFIG_EXTRA_OPTIMIZATION))" \
 	HOSTCFLAGS="$(HOST_CFLAGS) -Wall -Wmissing-prototypes -Wstrict-prototypes" \
 	CROSS_COMPILE="$(KERNEL_CROSS)" \
 	ARCH="$(LINUX_KARCH)" \
diff --git a/target/linux/generic/pending-5.10/201-extra_optimization.patch b/target/linux/generic/pending-5.10/201-extra_optimization.patch
index cb1de80764..dcf39c574f 100644
--- a/target/linux/generic/pending-5.10/201-extra_optimization.patch
+++ b/target/linux/generic/pending-5.10/201-extra_optimization.patch
@@ -14,18 +14,12 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
 
 --- a/Makefile
 +++ b/Makefile
-@@ -735,11 +735,11 @@ KBUILD_CFLAGS	+= $(call cc-disable-warni
- KBUILD_CFLAGS	+= $(call cc-disable-warning, address-of-packed-member)
- 
- ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
--KBUILD_CFLAGS += -O2
-+KBUILD_CFLAGS += -O2 $(EXTRA_OPTIMIZATION)
+@@ -739,7 +739,7 @@ KBUILD_CFLAGS += -O2
  else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3
--KBUILD_CFLAGS += -O3
-+KBUILD_CFLAGS += -O3 $(EXTRA_OPTIMIZATION)
+ KBUILD_CFLAGS += -O3
  else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 -KBUILD_CFLAGS += -Os
-+KBUILD_CFLAGS += -Os -fno-reorder-blocks -fno-tree-ch $(EXTRA_OPTIMIZATION)
++KBUILD_CFLAGS += -Os -fno-reorder-blocks -fno-tree-ch
  endif
  
  # Tell gcc to never replace conditional load with a non-conditional one
diff --git a/target/linux/generic/pending-5.15/201-extra_optimization.patch b/target/linux/generic/pending-5.15/201-extra_optimization.patch
index 5300a5c4ab..96e93dde9b 100644
--- a/target/linux/generic/pending-5.15/201-extra_optimization.patch
+++ b/target/linux/generic/pending-5.15/201-extra_optimization.patch
@@ -14,18 +14,12 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
 
 --- a/Makefile
 +++ b/Makefile
-@@ -752,11 +752,11 @@ KBUILD_CFLAGS	+= $(call cc-disable-warni
- KBUILD_CFLAGS	+= $(call cc-disable-warning, address-of-packed-member)
- 
- ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
--KBUILD_CFLAGS += -O2
-+KBUILD_CFLAGS += -O2 $(EXTRA_OPTIMIZATION)
+@@ -756,7 +756,7 @@ KBUILD_CFLAGS += -O2
  else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3
--KBUILD_CFLAGS += -O3
-+KBUILD_CFLAGS += -O3 $(EXTRA_OPTIMIZATION)
+ KBUILD_CFLAGS += -O3
  else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 -KBUILD_CFLAGS += -Os
-+KBUILD_CFLAGS += -Os -fno-reorder-blocks -fno-tree-ch $(EXTRA_OPTIMIZATION)
++KBUILD_CFLAGS += -Os -fno-reorder-blocks -fno-tree-ch
  endif
  
  # Tell gcc to never replace conditional load with a non-conditional one