diff --git a/sw/otbn/code-snippets/rsa_1024_dec_test.S b/sw/otbn/code-snippets/rsa_1024_dec_test.s
similarity index 100%
rename from sw/otbn/code-snippets/rsa_1024_dec_test.S
rename to sw/otbn/code-snippets/rsa_1024_dec_test.s
diff --git a/sw/otbn/code-snippets/rsa_1024_enc_test.S b/sw/otbn/code-snippets/rsa_1024_enc_test.s
similarity index 100%
rename from sw/otbn/code-snippets/rsa_1024_enc_test.S
rename to sw/otbn/code-snippets/rsa_1024_enc_test.s
diff --git a/sw/otbn/code-snippets/rules.mk b/sw/otbn/code-snippets/rules.mk
index 3a1b4b9..40d5d9a 100644
--- a/sw/otbn/code-snippets/rules.mk
+++ b/sw/otbn/code-snippets/rules.mk
@@ -83,13 +83,13 @@
 # Define any file-specific flags or dependencies
 #
 
-# rsa_1024_dec_test depends on modexp, defined in modexp.S
+# rsa_1024_dec_test depends on modexp, defined in modexp.s
 $(otbn-code-snippets-bin-dir)/rsa_1024_dec_test.elf: \
   $(otbn-code-snippets-obj-dir)/modexp.o
 $(otbn-code-snippets-bin-dir)/rsa_1024_dec_test.elf: \
   otbn-libs += $(otbn-code-snippets-obj-dir)/modexp.o
 
-# rsa_1024_enc_test depends on modexp_65537, defined in modexp.S
+# rsa_1024_enc_test depends on modexp_65537, defined in modexp.s
 $(otbn-code-snippets-bin-dir)/rsa_1024_enc_test.elf: \
   $(otbn-code-snippets-obj-dir)/modexp.o
 $(otbn-code-snippets-bin-dir)/rsa_1024_enc_test.elf: \