diff --git a/embed/extmod/modtrezorio/unix-msg-mock.h b/embed/extmod/modtrezorio/unix-msg-mock.h
index 31adc5b6..5bf7a38f 100644
--- a/embed/extmod/modtrezorio/unix-msg-mock.h
+++ b/embed/extmod/modtrezorio/unix-msg-mock.h
@@ -13,10 +13,13 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "../../unix/common.h"
 #include "../../trezorhal/usb.h"
 #include "../../trezorhal/touch.h"
 
+void __attribute__((noreturn)) __fatal_error(const char *expr, const char *msg, const char *file, int line, const char *func);
+
+#define ensure(expr, msg) (((expr) == sectrue) ? (void)0 : __fatal_error(#expr, msg, __FILE__, __LINE__, __func__))
+
 #define TREZOR_UDP_IFACE 0
 #define TREZOR_UDP_PORT 21324
 
diff --git a/embed/unix/common.c b/embed/unix/common.c
index d4085810..1d848b2d 100644
--- a/embed/unix/common.c
+++ b/embed/unix/common.c
@@ -31,3 +31,8 @@ void hal_delay(uint32_t ms)
 {
     usleep(1000 * ms);
 }
+
+void shutdown(void)
+{
+    exit(1);
+}
diff --git a/embed/unix/common.h b/embed/unix/common.h
index fde45ec8..d1daf8a1 100644
--- a/embed/unix/common.h
+++ b/embed/unix/common.h
@@ -9,4 +9,6 @@ void __attribute__((noreturn)) __fatal_error(const char *expr, const char *msg,
 
 void hal_delay(uint32_t ms);
 
+void shutdown(void);
+
 #endif