diff --git a/firmware/export/sdmmc.h b/firmware/export/sdmmc.h
index f84a7b96fa..ed075f82a3 100644
--- a/firmware/export/sdmmc.h
+++ b/firmware/export/sdmmc.h
@@ -27,7 +27,7 @@
 
 typedef struct
 {
-    bool initialized;
+    int initialized; /* 0, 1, or negative for errors */
 
     unsigned long read_timeout;     /* n * 8 clock cycles */
     unsigned long write_timeout;    /* n * 8 clock cycles */