diff --git a/util/stm32mon.c b/util/stm32mon.c
index e356e9bde9..dd66040bcc 100644
--- a/util/stm32mon.c
+++ b/util/stm32mon.c
@@ -54,7 +54,7 @@ struct stm32_def {
 	uint32_t page_size;
 } chip_defs[] = {
 	{0x416, "STM32L15xx", 0x08000000, 0x20000, 256},
-	{0x420, "STM32F100xx", 0x08000000, 0x10000, 1024},
+	{0x420, "STM32F100xx", 0x08000000, 0x20000, 1024},
 	{ 0 }
 };