diff --git a/libraries/AP_Filesystem/AP_Filesystem_ESP32.cpp b/libraries/AP_Filesystem/AP_Filesystem_ESP32.cpp
index fb36c9b1da035e..cc930fb73a3a2c 100644
--- a/libraries/AP_Filesystem/AP_Filesystem_ESP32.cpp
+++ b/libraries/AP_Filesystem/AP_Filesystem_ESP32.cpp
@@ -25,6 +25,12 @@
 
 extern const AP_HAL::HAL& hal;
 
+#if defined(HAL_ESP32_FLASHFS)
+#define ESP32_FILESYSTEM_SECTOR_SIZE FF_SS_WL
+#else
+#define ESP32_FILESYSTEM_SECTOR_SIZE FF_SS_SDCARD
+#endif
+
 int AP_Filesystem_ESP32::open(const char *fname, int flags, bool allow_absolute_paths)
 {
 #if FSDEBUG
@@ -170,7 +176,7 @@ int64_t AP_Filesystem_ESP32::disk_free(const char *path)
     /* Get total sectors and free sectors */
     fre_sect = fre_clust * fs->csize;
 
-    return (int64_t)fre_sect * FF_SS_SDCARD;
+    return (int64_t)fre_sect * ESP32_FILESYSTEM_SECTOR_SIZE;
 }
 
 // return total disk space in bytes
@@ -191,7 +197,7 @@ int64_t AP_Filesystem_ESP32::disk_space(const char *path)
     /* Get total sectors and free sectors */
     tot_sect = (fs->n_fatent - 2) * fs->csize;
 
-    return (int64_t)tot_sect * FF_SS_SDCARD;
+    return (int64_t)tot_sect * ESP32_FILESYSTEM_SECTOR_SIZE;
 }
 
 /*