diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 45069f54f6..062e718dc3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -124,7 +124,6 @@ config ARCH_CHIP_LC823450
 	select ARCH_HAVE_MULTICPU
 	select ARCH_HAVE_I2CRESET
 	select ARCH_GLOBAL_IRQDISABLE
-	select ARCH_IDLE_CUSTOM
 	---help---
 		ON Semiconductor LC823450 architectures (ARM dual Cortex-M3)
 
diff --git a/arch/arm/src/lc823450/Make.defs b/arch/arm/src/lc823450/Make.defs
index fa9049b6ad..9d8dad59eb 100644
--- a/arch/arm/src/lc823450/Make.defs
+++ b/arch/arm/src/lc823450/Make.defs
@@ -89,7 +89,7 @@ CHIP_CSRCS += lc823450_syscontrol.c lc823450_gpio.c
 
 # Configuration-dependent LC823450 files
 
-ifeq ($(CONFIG_ARCH_IDLE_CUSTOM),y)
+ifneq ($(CONFIG_ARCH_IDLE_CUSTOM),y)
 CHIP_CSRCS += lc823450_idle.c
 endif
 
diff --git a/include/unistd.h b/include/unistd.h
index ed6032039b..2ac53b5204 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -365,7 +365,7 @@ int     gethostname(FAR char *name, size_t size);
 int     sethostname(FAR const char *name, size_t size);
 #endif
 
-/* Get configurable system varaibles */
+/* Get configurable system variables */
 
 long    sysconf(int name);