As NSDL has already issued RPU release 2 for creation of etds returns w.e.f. 01.04.2005. I want to share that we can generate FVU file without having .csi file. Initially i was in view that we can not generate fvu file without .csi file. After a gap of 20 days, it has been found that we can leave blank place of .csi file and generate .fvu file.
However it is only temporary solution. Finally we should generate .fvu file with the use of .csi file. When we get fvu file with the support of csi file , it checks Challan Status/Challan Date/Challan Amount/Challan Sr. Number before uploading the fvu file. Therefore csi file is highly recommended for generation of fvu file.