diff --git a/storage/storage.c b/storage/storage.c
index fa6e90ca38..14d4114c50 100644
--- a/storage/storage.c
+++ b/storage/storage.c
@@ -330,30 +330,6 @@ static secbool auth_get(uint16_t key, const void **val, uint16_t *len) {
   return sectrue;
 }
 
-/*
- *  Generates a delay of random length. Use this to protect sensitive code
- * against fault injection.
- */
-static void wait_random(void) {
-#ifndef TREZOR_STORAGE_TEST
-  int wait = random32() & 0xff;
-  volatile int i = 0;
-  volatile int j = wait;
-  while (i < wait) {
-    if (i + j != wait) {
-      handle_fault("sanity check");
-    }
-    ++i;
-    --j;
-  }
-
-  // Double-check loop completion.
-  if (i != wait) {
-    handle_fault("loop completion check");
-  }
-#endif
-}
-
 static void derive_kek(uint32_t pin, const uint8_t *random_salt,
                        uint8_t kek[SHA256_DIGEST_LENGTH],
                        uint8_t keiv[SHA256_DIGEST_LENGTH]) {
diff --git a/storage/tests/c/Makefile b/storage/tests/c/Makefile
index a1fc96c2e3..610c2d1e9e 100644
--- a/storage/tests/c/Makefile
+++ b/storage/tests/c/Makefile
@@ -1,24 +1,36 @@
 CC = gcc
-CFLAGS = -Wall -Wshadow -Wextra -Wpedantic -Werror -fPIC -DTREZOR_STORAGE_TEST
+CFLAGS = -Wall -Wshadow -Wextra -Wpedantic -Werror -fPIC
 LIBS =
-INC = -I ../../../crypto -I ../../../storage -I .
-OBJ = flash.o common.o
-OBJ += ../../../storage/storage.o ../../../storage/norcow.o
-OBJ += ../../../crypto/pbkdf2.o
-OBJ += ../../../crypto/rand.o
-OBJ += ../../../crypto/chacha20poly1305/rfc7539.o
-OBJ += ../../../crypto/chacha20poly1305/chacha20poly1305.o
-OBJ += ../../../crypto/chacha20poly1305/poly1305-donna.o
-OBJ += ../../../crypto/chacha20poly1305/chacha_merged.o
-OBJ += ../../../crypto/hmac.o
-OBJ += ../../../crypto/sha2.o
-OBJ += ../../../crypto/memzero.o
+INC = -I ../../../crypto -I ../.. -I .
+BASE = ../../../
+
+SRC  = storage/tests/c/flash.c
+SRC += storage/tests/c/common.c
+SRC += storage/storage.c
+SRC += storage/norcow.c
+SRC += crypto/pbkdf2.c
+SRC += crypto/rand.c
+SRC += crypto/chacha20poly1305/rfc7539.c
+SRC += crypto/chacha20poly1305/chacha20poly1305.c
+SRC += crypto/chacha20poly1305/poly1305-donna.c
+SRC += crypto/chacha20poly1305/chacha_merged.c
+SRC += crypto/hmac.c
+SRC += crypto/sha2.c
+SRC += crypto/memzero.c
+
+OBJ = $(SRC:%.c=build/%.o)
+
 OUT = libtrezor-storage.so
 
 $(OUT): $(OBJ)
 	$(CC) $(CFLAGS) $(LIBS) $(OBJ) -shared -o $(OUT)
 
-%.o: %.c %.h
+build/crypto/chacha20poly1305/chacha_merged.o: $(BASE)crypto/chacha20poly1305/chacha_merged.c
+	mkdir -p $(@D)
+	$(CC) $(CFLAGS) $(INC) -c $< -o $@
+
+build/%.o: $(BASE)%.c $(BASE)%.h
+	mkdir -p $(@D)
 	$(CC) $(CFLAGS) $(INC) -c $< -o $@
 
 clean:
diff --git a/storage/tests/c/common.c b/storage/tests/c/common.c
index b3f9b7ffce..b53e1c34d4 100644
--- a/storage/tests/c/common.c
+++ b/storage/tests/c/common.c
@@ -23,6 +23,8 @@
 
 #include "common.h"
 
+void wait_random(void) {}
+
 void __shutdown(void) {
   printf("SHUTDOWN\n");
   exit(3);
diff --git a/storage/tests/c/common.h b/storage/tests/c/common.h
index eaa0773790..cfab1fcf85 100644
--- a/storage/tests/c/common.h
+++ b/storage/tests/c/common.h
@@ -22,6 +22,8 @@
 
 #include "secbool.h"
 
+void wait_random(void);
+
 void __fatal_error(const char *expr, const char *msg, const char *file,
                    int line, const char *func);
 void error_shutdown(const char *line1, const char *line2, const char *line3,