diff --git a/ion/src/device/shared/drivers/exam_mode.cpp b/ion/src/device/shared/drivers/exam_mode.cpp
index 96e10a2d0..3ae01315c 100644
--- a/ion/src/device/shared/drivers/exam_mode.cpp
+++ b/ion/src/device/shared/drivers/exam_mode.cpp
@@ -50,6 +50,7 @@ size_t firstOneBitInByte(int i) {
 uint8_t * SignificantExamModeAddress() {
   uint32_t * persitence_start_32 = (uint32_t *)&_exam_mode_buffer_start;
   uint32_t * persitence_end_32 = (uint32_t *)&_exam_mode_buffer_end;
+  assert(persitence_end_32 - persitence_start_32 % 4 == 0);
   while (persitence_start_32 < persitence_end_32 && *persitence_start_32 == 0x0) {
     // Scan by groups of 32 bits to reach first non-zero bit
     persitence_start_32++;