SetFilePointerEx doesn't seek my memory flash, why is this?

[Gilberto Gil]

Hello...I've a problems trying to move the pointer forward.. I'm trying to read my flash memory as array of bytes... Using SetFilePointerE x API function I've already did it, but, the problems is that it always read begening at 0 byte, I can't begin with offset of 512 bytes for example... why is this.....Note: it works pretty well seeking a file like .txt file. Some help.. please....I really need some help..

My code:

SafeFileHandle ptrFile = CreateFile("\\\\.\\u:", DesiredAccess.GENERIC_READ | DesiredAccess.GENERIC_WRITE, ShareMode.FILE_SHARE_READ_AND_WRITE, IntPtr.Zero, CreationDisposition.OPEN_EXISTING, FlagsAndAttributes.FILE_ATTRIBUTE_NORMAL, IntPtr.Zero);
 
        byte[] buffer = new byte[512];
 
        uint readed = 0;
        try
        {
           bool retor = SetFilePointerEx(ptrFile, 512, IntPtr.Zero,      MoveMethod.FILE_BEGIN);
        }
        catch (Exception)
        {
           throw new Win32Exception(Marshal.GetLastWin32Error());
        }
 
        bool b = ReadFile(ptrFile, buffer,512 , out readed, IntPtr.Zero)

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