@@ -70,6 +70,7 @@ - Qt: Add hex index to palette view
  - Qt: Add transformation matrix info to sprite view
  - Qt: Memory viewer now supports editing decimal values directly (closes mgba.io/i/1705)
  - Util: Reset vector size on deinit
+ - VFS: Change semantics of VFile.sync on mapped files (fixes mgba.io/i/1730)
 
 0.8.3: (2020-08-03)
 Emulation fixes:

@@ -47,7 +47,7 @@ void* (*map)(struct VFile* vf, size_t size, int flags);
 	void (*unmap)(struct VFile* vf, void* memory, size_t size);
 	void (*truncate)(struct VFile* vf, size_t size);
 	ssize_t (*size)(struct VFile* vf);
-	bool (*sync)(struct VFile* vf, const void* buffer, size_t size);
+	bool (*sync)(struct VFile* vf, void* buffer, size_t size);
 };
 
 struct VDirEntry {

@@ -38,7 +38,7 @@ static void* _vf3dMap(struct VFile* vf, size_t size, int flags);
 static void _vf3dUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vf3dTruncate(struct VFile* vf, size_t size);
 static ssize_t _vf3dSize(struct VFile* vf);
-static bool _vf3dSync(struct VFile* vf, const void* buffer, size_t size);
+static bool _vf3dSync(struct VFile* vf, void* buffer, size_t size);
 
 static bool _vd3dClose(struct VDir* vd);
 static void _vd3dRewind(struct VDir* vd);
@@ -160,14 +160,12 @@ FSFILE_GetSize(vf3d->handle, &size);
 	return size;
 }
 
-static bool _vf3dSync(struct VFile* vf, const void* buffer, size_t size) {
+static bool _vf3dSync(struct VFile* vf, void* buffer, size_t size) {
 	struct VFile3DS* vf3d = (struct VFile3DS*) vf;
 	if (buffer) {
 		u32 sizeWritten;
 		Result res = FSFILE_Write(vf3d->handle, &sizeWritten, 0, buffer, size, FS_WRITE_FLUSH);
-		if (res) {
-			return false;
-		}
+		return R_SUCCEEDED(res);
 	}
 	FSFILE_Flush(vf3d->handle);
 	return true;

@@ -40,7 +40,7 @@ static void* _vfsceMap(struct VFile* vf, size_t size, int flags);
 static void _vfsceUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vfsceTruncate(struct VFile* vf, size_t size);
 static ssize_t _vfsceSize(struct VFile* vf);
-static bool _vfsceSync(struct VFile* vf, const void* memory, size_t size);
+static bool _vfsceSync(struct VFile* vf, void* memory, size_t size);
 
 static bool _vdsceClose(struct VDir* vd);
 static void _vdsceRewind(struct VDir* vd);
@@ -146,13 +146,14 @@ sceIoLseek(vfsce->fd, cur, SEEK_SET);
 	return end;
 }
 
-bool _vfsceSync(struct VFile* vf, const void* buffer, size_t size) {
+bool _vfsceSync(struct VFile* vf, void* buffer, size_t size) {
 	struct VFileSce* vfsce = (struct VFileSce*) vf;
 	if (buffer && size) {
 		SceOff cur = sceIoLseek(vfsce->fd, 0, SEEK_CUR);
 		sceIoLseek(vfsce->fd, 0, SEEK_SET);
-		sceIoWrite(vfsce->fd, buffer, size);
+		int res = sceIoWrite(vfsce->fd, buffer, size);
 		sceIoLseek(vfsce->fd, cur, SEEK_SET);
+		return res == size;
 	}
 	return sceIoSyncByFd(vfsce->fd) >= 0;
 }
@@ -362,4 +363,4 @@ bool VDirCreate(const char* path) {
 	// TODO: Verify vitasdk explanation of return values
 	sceIoMkdir(path, 0777);
 	return true;
-}+}

@@ -73,8 +73,9 @@ f = ffi.from_handle(vfp.fileobj)
     if buffer and size:
         pos = f.tell()
         f.seek(0, os.SEEK_SET)
-        _vfpWrite(vf, buffer, size)
+        res = _vfpWrite(vf, buffer, size)
         f.seek(pos, os.SEEK_SET)
+        return res == size
     f.flush()
     os.fsync()
     return True

@@ -22,4 +22,4 @@ PYEXPORT void* _vfpMap(struct VFile* vf, size_t size, int flags);
 PYEXPORT void _vfpUnmap(struct VFile* vf, void* memory, size_t size);
 PYEXPORT void _vfpTruncate(struct VFile* vf, size_t size);
 PYEXPORT ssize_t _vfpSize(struct VFile* vf);
-PYEXPORT bool _vfpSync(struct VFile* vf, const void* buffer, size_t size);
+PYEXPORT bool _vfpSync(struct VFile* vf, void* buffer, size_t size);

@@ -42,7 +42,7 @@ static void* _vfdMap(struct VFile* vf, size_t size, int flags);
 static void _vfdUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vfdTruncate(struct VFile* vf, size_t size);
 static ssize_t _vfdSize(struct VFile* vf);
-static bool _vfdSync(struct VFile* vf, const void* buffer, size_t size);
+static bool _vfdSync(struct VFile* vf, void* buffer, size_t size);
 
 struct VFile* VFileOpenFD(const char* path, int flags) {
 	if (!path) {
@@ -195,7 +195,7 @@ }
 	return stat.st_size;
 }
 
-static bool _vfdSync(struct VFile* vf, const void* buffer, size_t size) {
+static bool _vfdSync(struct VFile* vf, void* buffer, size_t size) {
 	UNUSED(buffer);
 	UNUSED(size);
 	struct VFileFD* vfd = (struct VFileFD*) vf;
@@ -206,7 +206,7 @@ #else
 	futimes(vfd->fd, NULL);
 #endif
 	if (buffer && size) {
-		return msync(buffer, size, MS_SYNC) == 0;
+		return msync(buffer, size, MS_ASYNC) == 0;
 	}
 	return fsync(vfd->fd) == 0;
 #else
@@ -217,7 +217,7 @@ GetSystemTime(&st);
 	SystemTimeToFileTime(&st, &ft);
 	SetFileTime(h, NULL, &ft, &ft);
 	if (buffer && size) {
-		FlushViewOfFile(buffer, size);
+		return FlushViewOfFile(buffer, size);
 	}
 	return FlushFileBuffers(h);
 #endif

@@ -19,7 +19,7 @@ static void* _vffMap(struct VFile* vf, size_t size, int flags);
 static void _vffUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vffTruncate(struct VFile* vf, size_t size);
 static ssize_t _vffSize(struct VFile* vf);
-static bool _vffSync(struct VFile* vf, const void* buffer, size_t size);
+static bool _vffSync(struct VFile* vf, void* buffer, size_t size);
 
 struct VFile* VFileFIFO(struct CircleBuffer* backing) {
 	if (!backing) {
@@ -94,7 +94,7 @@ struct VFileFIFO* vff = (struct VFileFIFO*) vf;
 	return CircleBufferSize(vff->backing);
 }
 
-static bool _vffSync(struct VFile* vf, const void* buffer, size_t size) {
+static bool _vffSync(struct VFile* vf, void* buffer, size_t size) {
 	UNUSED(vf);
 	UNUSED(buffer);
 	UNUSED(size);

@@ -24,7 +24,7 @@ static void* _vffMap(struct VFile* vf, size_t size, int flags);
 static void _vffUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vffTruncate(struct VFile* vf, size_t size);
 static ssize_t _vffSize(struct VFile* vf);
-static bool _vffSync(struct VFile* vf, const void* buffer, size_t size);
+static bool _vffSync(struct VFile* vf, void* buffer, size_t size);
 
 struct VFile* VFileFOpen(const char* path, const char* mode) {
 	if (!path && !mode) {
@@ -144,13 +144,14 @@ fseek(vff->file, pos, SEEK_SET);
 	return size;
 }
 
-static bool _vffSync(struct VFile* vf, const void* buffer, size_t size) {
+static bool _vffSync(struct VFile* vf, void* buffer, size_t size) {
 	struct VFileFILE* vff = (struct VFileFILE*) vf;
 	if (buffer && size) {
 		long pos = ftell(vff->file);
 		fseek(vff->file, 0, SEEK_SET);
-		fwrite(buffer, size, 1, vff->file);
+		size_t res = fwrite(buffer, size, 1, vff->file);
 		fseek(vff->file, pos, SEEK_SET);
+		return res == 1;
 	}
 	return fflush(vff->file) == 0;
 }

@@ -58,7 +58,7 @@ static void* _vf7zMap(struct VFile* vf, size_t size, int flags);
 static void _vf7zUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vf7zTruncate(struct VFile* vf, size_t size);
 static ssize_t _vf7zSize(struct VFile* vf);
-static bool _vf7zSync(struct VFile* vf, const void* buffer, size_t size);
+static bool _vf7zSync(struct VFile* vf, void* buffer, size_t size);
 
 static bool _vd7zClose(struct VDir* vd);
 static void _vd7zRewind(struct VDir* vd);
@@ -327,7 +327,7 @@ // TODO
 	return false;
 }
 
-bool _vf7zSync(struct VFile* vf, const void* memory, size_t size) {
+bool _vf7zSync(struct VFile* vf, void* memory, size_t size) {
 	UNUSED(vf);
 	UNUSED(memory);
 	UNUSED(size);

@@ -28,7 +28,7 @@ static void _vfmUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vfmTruncate(struct VFile* vf, size_t size);
 static void _vfmTruncateNoop(struct VFile* vf, size_t size);
 static ssize_t _vfmSize(struct VFile* vf);
-static bool _vfmSync(struct VFile* vf, const void* buffer, size_t size);
+static bool _vfmSync(struct VFile* vf, void* buffer, size_t size);
 
 struct VFile* VFileFromMemory(void* mem, size_t size) {
 	if (!mem || !size) {
@@ -297,7 +297,7 @@ struct VFileMem* vfm = (struct VFileMem*) vf;
 	return vfm->size;
 }
 
-bool _vfmSync(struct VFile* vf, const void* buffer, size_t size) {
+bool _vfmSync(struct VFile* vf, void* buffer, size_t size) {
 	UNUSED(vf);
 	UNUSED(buffer);
 	UNUSED(size);

@@ -74,7 +74,7 @@ static void* _vfzMap(struct VFile* vf, size_t size, int flags);
 static void _vfzUnmap(struct VFile* vf, void* memory, size_t size);
 static void _vfzTruncate(struct VFile* vf, size_t size);
 static ssize_t _vfzSize(struct VFile* vf);
-static bool _vfzSync(struct VFile* vf, const void* buffer, size_t size);
+static bool _vfzSync(struct VFile* vf, void* buffer, size_t size);
 
 static bool _vdzClose(struct VDir* vd);
 static void _vdzRewind(struct VDir* vd);
@@ -426,7 +426,7 @@ // TODO
 	return false;
 }
 
-bool _vfzSync(struct VFile* vf, const void* memory, size_t size) {
+bool _vfzSync(struct VFile* vf, void* memory, size_t size) {
 	UNUSED(vf);
 	UNUSED(memory);
 	UNUSED(size);
@@ -654,7 +654,7 @@ // TODO
 	return false;
 }
 
-bool _vfzSync(struct VFile* vf, const void* memory, size_t size) {
+bool _vfzSync(struct VFile* vf, void* memory, size_t size) {
 	UNUSED(vf);
 	UNUSED(memory);
 	UNUSED(size);