diff --git a/ports/nrf/mpconfigport.h b/ports/nrf/mpconfigport.h
index d1e9665dee..92b87a036b 100644
--- a/ports/nrf/mpconfigport.h
+++ b/ports/nrf/mpconfigport.h
@@ -75,7 +75,13 @@
 #define MICROPY_FATFS_LFN_CODE_PAGE    437 /* 1=SFN/ANSI 437=LFN/U.S.(OEM) */
 #define MICROPY_FATFS_USE_LABEL        (1)
 #define MICROPY_FATFS_RPATH            (2)
-#define MICROPY_FATFS_MULTI_PARTITION  (1)
+#define MICROPY_FATFS_MULTI_PARTITION  (0)
+
+#if NRF51
+    #define MICROPY_FATFS_MAX_SS       (1024)
+#else
+    #define MICROPY_FATFS_MAX_SS       (4096)
+#endif
 
 // TODO these should be generic, not bound to fatfs
 #define mp_type_fileio fatfs_type_fileio