diff --git a/arch/arm/src/armv6-m/arm_dispatch_syscall.S b/arch/arm/src/armv6-m/arm_dispatch_syscall.S
index 20b341477ab..9d1d73c1ce8 100644
--- a/arch/arm/src/armv6-m/arm_dispatch_syscall.S
+++ b/arch/arm/src/armv6-m/arm_dispatch_syscall.S
@@ -89,6 +89,7 @@ arm_dispatch_syscall:
 	lsl r0, r0, #2                             /* R0=Offset of the stub for this syscall */
 	ldr r4, [r4, r0]                           /* R4=Address of the stub for this syscall */
 	blx r4                                     /* Call the stub (modifies lr) */
+	ldr r4, [sp, #0]                           /* Restore r4 */
 	add sp, sp, #32                            /* Destroy the stack frame */
 	mov r2, r0                                 /* R2=Save return value in R2 */
 	mov r0, SYS_syscall_return                 /* R0=SYS_syscall_return */
diff --git a/arch/arm/src/armv7-m/arm_dispatch_syscall.S b/arch/arm/src/armv7-m/arm_dispatch_syscall.S
index fcc87656420..6b2b88bfd5f 100644
--- a/arch/arm/src/armv7-m/arm_dispatch_syscall.S
+++ b/arch/arm/src/armv7-m/arm_dispatch_syscall.S
@@ -78,9 +78,8 @@
 arm_dispatch_syscall:
 	.cfi_sections	.debug_frame
 	.cfi_startproc
-	mov r11, sp
-	.cfi_register sp, r11
 	sub	sp, sp, #32
+	.cfi_def_cfa_offset 32
 	str	r4, [sp, #0]
 	.cfi_offset r4, 0
 	str	r5, [sp, #4]