AS Verification failed for Cyclone-I

[Altera_Forum]

Hello all, 

I am trying to configure a Cyclone-I FPGA using EPCS4 configuration device. I am using Active Serial programming. The programming is going through fine, but I get the verification failed error. :confused:  I tried changing the EPCS4 device, but I still get the same problem. I checked the VCC and GND connections to EPCS4, and they are fine. I have another board with exactly the same circuitry, and this also gives the same problem. So it cannot be that the FPGA is bad. So we can rule out issues with FPGA and EPCS4.  I have a third board, which differs from the first two boards in only 4 logic connections. This board is getting successfully programmed and verified.  I can't understand what may be the issue. Can someone please help me out.  regards, rajesh

[Altera_Forum]

One possible reason is that AS interface is more susceptible to signal integrity problems than JTAG. If you have a JTAG interface too, you should try to access the EPCS device through indirect JTAG programming (after generating a JIC file). 

 It would be interesting to know, at which memory location the verify fails, and if it's always the same. Another question is, if the configuration is accepted by the FPGA. It won't, if a CRC error is detected.