diff --git b/rules.mk a/rules.mk
index 25bd083..bd3edb9 100644
--- b/rules.mk
+++ a/rules.mk
@@ -12,8 +12,6 @@ MODULE_RUSTFLAGS += \
 	--cfg 'feature="alloc"' \
 
 MODULE_LIBRARY_DEPS := \
-	external/rust/crates/base64ct \
 	external/rust/crates/der \
-	external/rust/crates/sha2 \
 
 include make/library.mk