diff --git a/libretro.cpp b/libretro.cpp
index 19a7b684..6d45c678 100644
--- a/libretro.cpp
+++ b/libretro.cpp
@@ -1568,12 +1568,17 @@ static void InitCommon(std::vector<CDIF *> *CDInterfaces, const bool EmulateMemc
       abort();
 
    {
+      const char *biospath = MDFN_MakeFName(MDFNMKF_FIRMWARE, 
+            0, MDFN_GetSettingS(biospath_sname).c_str());
+      RFILE *BIOSFile      = filestream_open(biospath,
+            RETRO_VFS_FILE_ACCESS_READ,
+            RETRO_VFS_FILE_ACCESS_HINT_NONE);
 
-      const char *biospath = MDFN_MakeFName(MDFNMKF_FIRMWARE, 0, MDFN_GetSettingS(biospath_sname).c_str());
-
-      FileStream BIOSFile(biospath, MODE_READ);
-
-      BIOSFile.read(BIOSROM->data8, 512 * 1024);
+      if (BIOSFile)
+      {
+         filestream_read(BIOSFile, BIOSROM->data8, 512 * 1024);
+         filestream_close(BIOSFile);
+      }
    }
 
    i = 0;
diff --git a/mednafen/cdrom/CDAccess_Image.cpp b/mednafen/cdrom/CDAccess_Image.cpp
index 7174e974..c1ebea62 100644
--- a/mednafen/cdrom/CDAccess_Image.cpp
+++ b/mednafen/cdrom/CDAccess_Image.cpp
@@ -320,22 +320,27 @@ int CDAccess_Image::LoadSBI(const char* sbi_path)
    uint8 header[4];
    uint8 ed[4 + 10];
    uint8 tmpq[12];
-   FileStream sbis(sbi_path, MODE_READ);
+   RFILE *sbis      = filestream_open(sbi_path, 
+         RETRO_VFS_FILE_ACCESS_READ,
+         RETRO_VFS_FILE_ACCESS_HINT_NONE);
 
-   sbis.read(header, 4);
-
-   if(memcmp(header, "SBI\0", 4))
+   if (!sbis)
       return -1;
 
-   while(sbis.read(ed, sizeof(ed), false) == sizeof(ed))
+   filestream_read(sbis, header, 4);
+
+   if(memcmp(header, "SBI\0", 4))
+      goto error;
+
+   while(filestream_read(sbis, ed, sizeof(ed)) == sizeof(ed))
    {
       /* Bad BCD MSF offset in SBI file. */
       if(!BCD_is_valid(ed[0]) || !BCD_is_valid(ed[1]) || !BCD_is_valid(ed[2]))
-         return -1;
+         goto error;
 
       /* Unrecognized boogly oogly in SBI file */
       if(ed[3] != 0x01)
-         return -1;
+         goto error;
 
       memcpy(tmpq, &ed[4], 10);
 
@@ -350,7 +355,13 @@ int CDAccess_Image::LoadSBI(const char* sbi_path)
 
    //MDFN_printf(_("Loaded Q subchannel replacements for %zu sectors.\n"), SubQReplaceMap.size());
    log_cb(RETRO_LOG_INFO, "[Image] Loaded SBI file %s\n", sbi_path);
+   filestream_close(sbis);
    return 0;
+
+error:
+   if (sbis)
+      filestream_close(sbis);
+   return -1;
 }
 
 bool CDAccess_Image::ImageOpen(const char *path, bool image_memcache)
diff --git a/mednafen/cdrom/CDAccess_PBP.cpp b/mednafen/cdrom/CDAccess_PBP.cpp
index b5458e8c..17ff28ad 100644
--- a/mednafen/cdrom/CDAccess_PBP.cpp
+++ b/mednafen/cdrom/CDAccess_PBP.cpp
@@ -684,22 +684,27 @@ int CDAccess_PBP::LoadSBI(const char* sbi_path)
    uint8 header[4];
    uint8 ed[4 + 10];
    uint8 tmpq[12];
-   FileStream sbis(sbi_path, MODE_READ);
+   RFILE *sbis      = filestream_open(sbi_path,
+         RETRO_VFS_FILE_ACCESS_READ,
+         RETRO_VFS_FILE_ACCESS_HINT_NONE);
 
-   sbis.read(header, 4);
-
-   if(memcmp(header, "SBI\0", 4))
+   if (!sbis)
       return -1;
 
-   while(sbis.read(ed, sizeof(ed), false) == sizeof(ed))
+   filestream_read(sbis, header, 4);
+
+   if(memcmp(header, "SBI\0", 4))
+      goto error;
+
+   while(filestream_read(sbis, ed, sizeof(ed)) == sizeof(ed))
    {
       /* Bad BCD MSF offset in SBI file. */
       if(!BCD_is_valid(ed[0]) || !BCD_is_valid(ed[1]) || !BCD_is_valid(ed[2]))
-         return -1;
+         goto error;
 
       /* Unrecognized boogly oogly in SBI file */
       if(ed[3] != 0x01)
-         return -1;
+         goto error;
 
       memcpy(tmpq, &ed[4], 10);
 
@@ -716,7 +721,13 @@ int CDAccess_PBP::LoadSBI(const char* sbi_path)
    MDFN_printf(_("Loaded Q subchannel replacements for %zu sectors.\n"), SubQReplaceMap.size());
 #endif
    log_cb(RETRO_LOG_INFO, "[PBP] Loaded SBI file %s\n", sbi_path);
+   filestream_close(sbis);
    return 0;
+
+error:
+   if (sbis)
+      filestream_close(sbis);
+   return -1;
 }
 
 void CDAccess_PBP::Eject(bool eject_status)
diff --git a/mednafen/psx/frontio.cpp b/mednafen/psx/frontio.cpp
index 0a4896d0..fefd7772 100644
--- a/mednafen/psx/frontio.cpp
+++ b/mednafen/psx/frontio.cpp
@@ -945,12 +945,18 @@ void FrontIO::LoadMemcard(unsigned int which, const char *path)
 
  if(DevicesMC[which]->GetNVSize())
  {
-    FileStream mf(path, MODE_READ);
+    RFILE *mf = filestream_open(path, RETRO_VFS_FILE_ACCESS_READ, 
+          RETRO_VFS_FILE_ACCESS_HINT_NONE);
 
-    mf.read(DevicesMC[which]->GetNVData(), (1 << 17));
+    if (!mf)
+       return;
+
+    filestream_read(mf, DevicesMC[which]->GetNVData(), (1 << 17));
 
     DevicesMC[which]->WriteNV(DevicesMC[which]->GetNVData(), 0, (1 << 17));
     DevicesMC[which]->ResetNVDirtyCount();		// There's no need to rewrite the file if it's the same data.
+
+    filestream_close(mf);
  }
 }
 
@@ -971,14 +977,19 @@ void FrontIO::SaveMemcard(unsigned int which, const char *path)
 
  if(DevicesMC[which]->GetNVSize() && DevicesMC[which]->GetNVDirtyCount())
  {
-  FileStream mf(path, MODE_WRITE);	// TODO: MODE_WRITE_ATOMIC_OVERWRITE
+    RFILE *mf = filestream_open(path, 
+          RETRO_VFS_FILE_ACCESS_WRITE,
+          RETRO_VFS_FILE_ACCESS_HINT_NONE);
 
-  DevicesMC[which]->ReadNV(DevicesMC[which]->GetNVData(), 0, (1 << 17));
-  mf.write(DevicesMC[which]->GetNVData(), (1 << 17));
+    if (!mf)
+       return;
 
-  mf.close();	// Call before resetting the NV dirty count!
+    DevicesMC[which]->ReadNV(DevicesMC[which]->GetNVData(), 0, (1 << 17));
+    filestream_write(mf, DevicesMC[which]->GetNVData(), (1 << 17));
 
-  DevicesMC[which]->ResetNVDirtyCount();
+    filestream_close(mf);	// Call before resetting the NV dirty count!
+
+    DevicesMC[which]->ResetNVDirtyCount();
  }
 }