diff --git a/lib/Makefile b/lib/Makefile
index ae84833..dd36f25 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -85,13 +85,13 @@
 ifdef CONFIG_SPL_BUILD
 # SPL U-Boot may use full-printf, tiny-printf or none at all
 ifdef CONFIG_USE_TINY_PRINTF
-obj-$(CONFIG_SPL_SERIAL_SUPPORT) += tiny-printf.o panic.o
+obj-$(CONFIG_SPL_SERIAL_SUPPORT) += tiny-printf.o panic.o strto.o
 else
-obj-$(CONFIG_SPL_SERIAL_SUPPORT) += vsprintf.o panic.o
+obj-$(CONFIG_SPL_SERIAL_SUPPORT) += vsprintf.o panic.o strto.o
 endif
 else
 # Main U-Boot always uses the full printf support
-obj-y += vsprintf.o panic.o
+obj-y += vsprintf.o panic.o strto.o
 endif
 
 subdir-ccflags-$(CONFIG_CC_OPTIMIZE_LIBS_FOR_SPEED) += -O2