diff --git a/boards/arm/imx9/imx93-qsb/configs/nsh-ddr/defconfig b/boards/arm/imx9/imx93-qsb/configs/nsh-ddr/defconfig
index 7476b81e35d7e..e0646ad4ff817 100644
--- a/boards/arm/imx9/imx93-qsb/configs/nsh-ddr/defconfig
+++ b/boards/arm/imx9/imx93-qsb/configs/nsh-ddr/defconfig
@@ -18,6 +18,7 @@ CONFIG_ARCH_INTERRUPTSTACK=4096
 CONFIG_ARCH_STACKDUMP=y
 CONFIG_ARMV8M_DTCM=y
 CONFIG_ARMV8M_ITCM=y
+CONFIG_ARMV8M_STRING_FUNCTION=n
 CONFIG_BOARD_LOOPSPERMSEC=613
 CONFIG_BOOT_RUNFROMSDRAM=y
 CONFIG_BUILTIN=y
diff --git a/boards/arm/imx9/imx93-qsb/configs/nsh/defconfig b/boards/arm/imx9/imx93-qsb/configs/nsh/defconfig
index 07ae1823ee5ca..f56027645bd3a 100644
--- a/boards/arm/imx9/imx93-qsb/configs/nsh/defconfig
+++ b/boards/arm/imx9/imx93-qsb/configs/nsh/defconfig
@@ -18,6 +18,7 @@ CONFIG_ARCH_INTERRUPTSTACK=4096
 CONFIG_ARCH_STACKDUMP=y
 CONFIG_ARMV8M_DTCM=y
 CONFIG_ARMV8M_ITCM=y
+CONFIG_ARMV8M_STRING_FUNCTION=n
 CONFIG_BOARD_LOOPSPERMSEC=2399
 CONFIG_BOOT_RUNFROMISRAM=y
 CONFIG_BUILTIN=y
diff --git a/boards/arm/imx9/imx93-qsb/configs/rpmsg/defconfig b/boards/arm/imx9/imx93-qsb/configs/rpmsg/defconfig
index 12f7101d8e869..758334fde798a 100644
--- a/boards/arm/imx9/imx93-qsb/configs/rpmsg/defconfig
+++ b/boards/arm/imx9/imx93-qsb/configs/rpmsg/defconfig
@@ -18,6 +18,7 @@ CONFIG_ARCH_INTERRUPTSTACK=4096
 CONFIG_ARCH_STACKDUMP=y
 CONFIG_ARMV8M_DTCM=y
 CONFIG_ARMV8M_ITCM=y
+CONFIG_ARMV8M_STRING_FUNCTION=n
 CONFIG_BOARD_LOOPSPERMSEC=2399
 CONFIG_BOOT_RUNFROMISRAM=y
 CONFIG_BUILTIN=y
diff --git a/libs/libc/machine/arm/armv8-m/Kconfig b/libs/libc/machine/arm/armv8-m/Kconfig
index 14189764e498a..7fad21c28b8b8 100644
--- a/libs/libc/machine/arm/armv8-m/Kconfig
+++ b/libs/libc/machine/arm/armv8-m/Kconfig
@@ -7,7 +7,7 @@ if ARCH_ARMV8M
 
 config ARMV8M_STRING_FUNCTION
 	bool "Enable optimized ARMv8M specific string function"
-	default n
+	default y
 	depends on ARCH_TOOLCHAIN_GNU
 	select ARMV8M_MEMCHR
 	select ARMV8M_MEMCPY