Help! Checksum error when downloading, can't upload.

[jeffs555]

I am trying to use IR to program a URC-6011b00. I can download from and IR correctly identifies the remote, and all the keys and codes appear as they were programed on the remote keypad. However, IR reports a checksum warning on every download saying "Expected $73 $8C, but found $8C $73". If I change something using setup on the remote, the checksum bytes change, but I still get checksum warning saying "Expected $xx $yy, but found $yy $xx" (ie the checksum bytes appear correct but are swapped). Any change I make using setup on the remote appears correctly in the downloaded data, but IR always reports the checksum error.

If I try to upload to the remote, it gives a single long flash instead of the 2 quick ones, and after that even trying to download gives the single long flash and doesn't work. The only way to get download to work again is to do a factory reset from the remote setup.(ie 981)

I am using the latest IR(7.15). It and all other files were just downloaded from this site. I am using a home built ultra parallel interface.(I am an electrical engineer and fairly certain it was built correctly). The EEPROM and JP1 connectors were installed by OFA when I sent it in for update several years ago. I have two URC-6011b00's and they both do the same thing. They are the only JP1 remotes I have. I am new to JP1, but am pretty sure that I have all the software and files installed correctly.

Thanks for any help anyone can give.

[Mark Pierson]

The EEPROM and JP1 connectors were installed by OFA when I sent it in for update several years ago.

If I'm not mistaken the remotes that UEI sends back as "upgrades" contain only a 1k EEPROM. The proper RDF to select for that would be 6_806_80 (URC-881x_801x_601x 1k).rdf. In IR's Select Remote Type dialog it will appear as URC-881x_801x_601x 1k (6_806_80).

[jeffs555]

Thanks, that is what it says in the title bar after a download, so I think it is using the correct RDF file still gives the checksum warning and won't upload correctly.

[The Robman]

ould you go to the Advanced menu and enable raw downloads, then use the Raw Download button to download your remote's memory and post the IR file in the Diagnosis Area. I'll take a look at it to see what's throwing the checksum off.

[jeffs555]

OK, I got it working, but had to modify the RDF file. I read the section in RDF3Spec.doc about checksum. The file 6_806_80 (URC-881x_801x_601x1k).rdf had a checksum section as follows:
[Checksums]
^$000:$002..$3FF

The raw data download always had FF in the last 3 locations, so I figured that shortening the checksum range would do one less XOR with FF. I changed the checksum section to
[Checksums]
^$000:$002..$3FE

It works like that and I can upload and download OK, but I suspect that the end range should actually be $3FC