Bug of fastboot? or exactly on device? I tried to flash sparsed images

[werasik2aa]

public bool UploadData(string path)
{
    //WRITE_D
    FileStream stream = new FileStream(path, FileMode.Open);
    string madx = Command("getvar:max-download-size").Payload;
    intMAX_DWN_SIZE = (int)new Int32Converter().ConvertFromString(madx);
    long totalenremain = stream.Length;
    long curlenremain = totalenremain >= MAX_DWN_SIZE ? MAX_DWN_SIZE : totalenremain;
    while (totalenremain > 0)
    {
        if (SendDataCommand(curlenremain))
        {
            var partname = stream.Name.Split('.')[0].Split('\\').Last();
            var writeEp = device.OpenEndpointWriter(WriteEndpointID.Ep01);
            LOG(0, "[Fastboot] Sending: ", partname);
            while (curlenremain > 0)
            {
                if (curlenremain < BLOCK_SIZE)
                {
                    TransferBlock(stream, new byte[curlenremain], (int)curlenremain);
                    totalenremain -= curlenremain;
                    curlenremain = 0;
                }
                else
                {
                    TransferBlock(stream, new byte[BLOCK_SIZE], BLOCK_SIZE);
                    totalenremain -= BLOCK_SIZE;
                    curlenremain -= BLOCK_SIZE;
                }
                Progress((int)(stream.Length - totalenremain), (int)stream.Length);
            }
            stream.Close();
            stream.Dispose();
            //READ_ED
            var resBuffer = new byte[64];
            ReadEp.Read(resBuffer, DefaultRWTimeout, out _);
            var strBuffer = Encoding.ASCII.GetString(resBuffer);
            if (strBuffer.Length < HEADER_SIZE)
                throw new Exception("Invalid response from device: " + strBuffer);
            if (GetStatus(new string(strBuffer.Take(HEADER_SIZE).ToArray())) != FastbootStatus.Ok)
                throw new Exception("Invalid status: " + strBuffer);
            else
            {
                LOG(0, "[Fastboot] Writing: ", partname);
                var res = Command("flash:" + partname).Payload;
                if (res.Contains("table doesn't exist"))
                {
                    LOG(1, "Skip Partition. ", res);
                    break;
                }
            }
        }
        else
        {
            stream.Close();
            stream.Dispose();
            return false;
        }
    }
    return true;
}

this code writes the fastboot image.
ALL good, but ramdisk.img wont flash
like my device aborting pipe...