Checksum bytes, downloads questions

Post by **ElizabethD** » Thu Mar 15, 2018 7:51 pm

I need reminders

Are checksum 2 bytes, just left of signature, stored in the remote or is it a product of IR or RMIR?
I have a discrepancy in one 6131-old and just want to follow it up a bit. Or ditch it.
Is there a way I can calculate the checksum from Raw data or from IR or RMIR file EASILY?

What is the difference between Download and Raw Download?

Post by **The Robman** » Thu Mar 15, 2018 9:24 pm

If you look at the RDF it tells you where the checksums are. This is from the 6131 RDF:

[Checksums]
^$000:$002..$3FC

That means that the checksum is at $000 (ie, the first byte) and it's calculated using the data in $002 thru $3FC. I assume the ^ symbol means it's an XOR.

There is a tool in IR.exe to calculate checksums, it's at Tools > Checksum Calculator.

A Raw Download gets the data directly from the remote with no manipulation, it's something that you do when you don't have an RDF or you don't trust it. A regular download goes through the RDF, which might cause some of the data to change.

Post by **ElizabethD** » Fri Mar 16, 2018 1:46 pm

Good thing google keeps old links!
Two years ago I had trouble uploading 6131 old remote, and we never solved it, and Rob, you too had something there as well:
https://www.hifi-remote.com/forums/viewtopic.php?t=16693
RMIR was aborting upload, just kicking me out with a java fatal error(s).
There, Graham suspected timing in jp1usb.dll and then batteries.

Well, before I contribute to a landfill, I tried again, this time using 981-reset remote, and noticed that when RMIR processes the file, the error log show signature that does not match what download saw.

So now I did raw download, and, holy smoke, it's different.
When I save raw download and load it back into RMIR, it doesn't match what I saved.
The difference is checkbytes, of course, and the contents of hex0100+.
In raw download it shows three 01 06 pairs. In standard download it shows three 01 04 pairs. And no matter if I Open raw download or standard download, the 01 04 comes in.
IR doesn't have raw download, though I see that enabling it is checked. Checksum matches what standard download in IR and RMIR display.
What do you think?

Post by **The Robman** » Fri Mar 16, 2018 2:33 pm

I think I'd need to see the files

Post by **ElizabethD** » Fri Mar 16, 2018 5:38 pm

Few files that I think are relevant:
https://www.hifi-remote.com/forums/dload ... e_id=25140
zipped and include a note to read. Open them in chronological (by date) sequence.

EDIT: Rob when I load the raw download(with PVR0 in name) into IR, IR Windows Title says 6131nw. Yet the remote is not nw, it's old style.
And raw data display is just like standard download, with checksum D4 2B.

Post by **The Robman** » Fri Mar 16, 2018 8:57 pm

Using IR.exe, have you tried to initialize the memory to all $FF, then do a 981 reset on it and start over? I noticed that even though you have "01 04 01 04 00 00" at $100, there is a lot of data after that, which means you have a lot of deleted upgrades. That upgrade data still plays a part in the checksum even though the upgrades themselves are logically deleted. You could also use the Clear Upper Memory command to just clean up that area.

Post by **ElizabethD** » Fri Mar 16, 2018 9:52 pm

That was going to be my question to see if some of those cleanup things would fix the remote. Didn't have the guts to do it.
So in IR I did both, fill $FF and cleared upper memory. Saved the file.
Yup, it sure got filled and cleared. edited: I did 981 reset.
Downloaded from the remote. The files are different.
This is stranger than fiction at this point.

I'll see tomorrow if RMIR will like it better.

EDIT:
oops, I forgot to write that I did 981 before downloading. Perhaps that made the files a bit different.
The stuff that was there weren't my upgrades. I gather that 981 sets it to a factory state and imagined that's what that stuff was. Default settings or something.[/b]

Post by **The Robman** » Sat Mar 17, 2018 9:29 am

Where did you get this 6131? Remember that they didn't ship with EEPROM chips, so either you got this from me (I soldered them in) or you sent it into UEI for an upgrade or some other source.

When I sold these on ebay I did load a butt load of upgrades into them, but I think I had formatted but otherwise empty EEPROMs in the ones that I sold to folks here. So if those deleted upgrades aren't yours, who's are they?

A 981 reset doesn't put phantom upgrades in there, lol, but it doesn't blank that area out either, it just resets the first 6 bytes at $100 to "01 04 01 04 00 00".

Post by **ElizabethD** » Sat Mar 17, 2018 8:24 pm

Oh yeah! That's the one from you with its lifetime warranty and support

(just kidding)

Rob, I have four 6131-old and one new. I have no idea how/where/when I got them. I think from you I got C7. Perhaps 6131. I remember that one 6131 was from some outfit in California. No clue which. It was all 7-10yrs ago.

Question - if the remote had extender in it, does 981 wipe out the extender cleanly? I may have had extender on this #2 remote. In fact I cannot find ANY old KM upgrades for it that don't indicate unextended state. Hmmm. Had to make two today in KM just to test things in IR. See Footnote below.

In IR after all that cleanup I added two device upgrades, TV and AUD, NEC1 and Panasonic combo.
Loaded it into RMIR, saved rmir. Tried to upload again and was tossed out by java.

Here's the fun part. Remote no longer controls my TV and AUD that worked fine after IR work.
IRscope reports Pioneer and RCA signals. I think this remote is cooked by RMIR. But IR will fix it as it did few times today.

In case you want to see the gory details:
https://www.hifi-remote.com/forums/dload ... e_id=25143
-----------
Footnote: Where did I get the upgrades that got deleted? I think when I was helping Herbie I saw his .rmir file which is extended. I recognized few setup codes which I never used 0618, 2000, 0032...
which is one reason I asked about 981 vs extender above. But I think he used default codes.

Post by **The Robman** » Sat Mar 17, 2018 8:56 pm

If you have broken out of extender mode and do a 981 reset, it just puts "01 04 01 04 00 00" at address $100 as that logically deletes all the upgrades, but it leaves all the junk in there. Much like when you delete a file on your PC, the file is still there, but the link to it has gone.

But loading all $FF into the memory and then doing a 981 reset produces what we call a "virgin" IR file.

Also, just FYI, the new and old 6131s are both exactly the same from a programming point of view.