Just a short update. I managed to leave the status register of the EPCS4 with the Block Protect Bits set to 001 which protects sector 7 and leaves sectors 0-6 unprotected. The Cyclone II part that I am using only requires 4 sectors (1.9 MBits of the 4 MBits available). Even so the ByteBlaster and the programming software obviously rely on a ChipErase Command which failed. Since I did not ask the programmer to "Verify", I was at a loss to explaining why things were not working. Using the processor interface it was clear that programming was not working. I used the Write Status Register command to reset the block protect bits back to zero and all was resolved.
Two lessons here:
- Always put things back the way you found them.
- Trust (the programmer), but verify the result.
Once burned, twice chastened