Z21 Maintenance Tool: Downlevelling Zimo Firmware

[RFS]

Because of a possible issue with the 40.5 firmware level of Zimo decoders, I'm trying to revert a couple of my MX634 decoders back to the level they were at, namely 36.5. But all attempts fail with the error message - 

 

"Error: decoder does not respond to any start-byte of the list".

 

CV8 is 145 for Zimo, CV144 is 0 (unlocked) and CV250 is 240 (start-byte for MX634).  Trying CTRL + ALT +Z is also unsuccessful. The decoder is in a Bachmann 2-EPB and the unit's lights come on during the process, so contact is not an issue. I have also tried with a programming track connected directly to the back of the Z21 with very short (50cm) wires. Again no joy. 

 

So has anyone managed to downlevel firmware using the tool? It even fails trying to re-flash 40.5.  I have been talking with Zimo but they do not know why the Roco tool does not work. I have raised a case with Roco.

 

This is the log:

 

 

Edited September 6, 2021 by RFS

[WIMorrison]

What are the issues with 40.5? I have a few decoders on 39.0 that I was going to upgrade and see if resolves a starting issue (MX634 wont always start in forwards until coaxed by DC running for a few minutes) but going by your experience perhaps best to avoid?

 

I have never tried to go back a version or 2 of firmware, only gone to newer versions - sorry 

[RFS]

8 hours ago, WIMorrison said:

What are the issues with 40.5? I have a few decoders on 39.0 that I was going to upgrade and see if resolves a starting issue (MX634 wont always start in forwards until coaxed by DC running for a few minutes) but going by your experience perhaps best to avoid?

 

I have never tried to go back a version or 2 of firmware, only gone to newer versions - sorry 

 

This is the issue - https://www.rmweb.co.uk/community/index.php?/topic/166751-zimo-decoders-traincontroller-and-accurate-stopping/

[WIMorrison]

Thanks - not sure I want to upgrade if I have to reprofile my locos

 

I might try it on one and see if I can reproduce your issue

[RFS]

1 hour ago, WIMorrison said:

Thanks - not sure I want to upgrade if I have to reprofile my locos

 

I might try it on one and see if I can reproduce your issue

 

Below is the response from Zimo (Stephn Hubinger) regarding the need to re-profile. He explains this was for the MX600 but I had to reprofile all of my Zimo decoders. The MX600Rs were 31.63 and the MX634s 36.5 so it must have been after that, so I don't know whether the change was before version 39. 

 

I'm able to reproduce the problem simply using TC's drag-and-drop: if it's a short journey over a couple of blocks the trains stop where they should, but a longer trip over 3-4 blocks and they stop short. Would be nice if you were able to reproduce that.

 

"Yes, please test … but for the MX600-series it is clear for me why and the re-scaling of CV#5 with the current software version for the MX600-series is not counted as bug, it was intended by ZIMO - so EVERY (!) customer how uses TC profiling AND has a MX600 in the loco has to re-perform the profiling after the MX600-update, before he/she should start testing again.

 

The MX600-series was (and partly still is) differently as any other comparable typically ZIMO decoderseries, because the design aim was to make a "affordable" ZIMO decoder - so cuts have been made regarding hardware (so cheaper/slower processor on board, no logic level outputs,…) and software (no motorola, no SUSI, no servo support,…). With the update to 40.5 it gets some features (so processor clock is doubled, more RailCom messages) … so ZIMO has decided later, that we give the MX600-serie (via free software update for the customers) some features, which all other typical ZIMO decoders have to close a little bit the gap to the other series … that includes the re-scaling of the max. speed also (so same CV#5 value in a MX600 with 40.5 is leading now to the same speed as the same CV#5 value in any other ZIMO decoder series (regardless of the software version it has loaded, so older like 37 also count) … that was not the case for the older MX600-software versions (so before the CV#5 internal scaling of the MX600 was different to any other ZIMO decoder series - now (with 40.5 loaded in the MX600) all ZIMO decoders series have the same CV#5 internal scaling)."

[jpendle]

Hi Robert,

 

I think that there may be more then just revision 40.5 coming into play here.

 

So first , mea culpa, I got my reply wrong in your other post. I am running revision 40.1 on all my profiled locos and have experienced no issues.

 

Second, and I think this is very relevant to what you are seeing, I found a significant speed difference between decoders running revision 31.5 and those running 37.8. I was trying to double head two identical N Gauge locos, one had an MX622N at rev 31.5 and the other had an MX617N at rev 37.8. The loco with the MX617N ran almost twice as fast as the one with the MX622N.

After upgrading the MX622N to 37.8 it's loco ran at almost the same speed as the MX17N equipped one.

 

So as you say that the MX634's were at 36.5, it may be that upgrading them to 37.8 (or higher) has had the same effect that I saw on my MX622N decoders.

I was never able to determine which specific firmware revision was responsible for changing the speed characteristics on my decoders.

 

I can also try upgrading one of my decoders from 40.1 to 40.5 to see if it has any material effect on its speed performance.

 

BTW, were you able to get your locos to run properly once they had been re-profiled, it seemed like you were still having issues, at the end of your other thread?

 

Regards,

 

John P

[RFS]

1 hour ago, jpendle said:

BTW, were you able to get your locos to run properly once they had been re-profiled, it seemed like you were still having issues, at the end of your other thread?

 

Regards,

 

John P

 

Yes - after reprofiling them they ran OK. One of the tasks with Traincontroller is then to adjust the brake compensation, so that the loco always stops precisely at the stop marker. Having done this and been pleased with the result, I was then surprised that when the locos ran on schedules they sometimes stopped short. Therefore my suspicion is that BEMF is coming into play, and perhaps the sampling is giving varying results depending on how long the loco has been on the move. Now just waiting for Roco to respond and explain why the downlevelling always fails. 

[WIMorrison]

This brings to mind a memory of a few locos needing reprofiling a while ago as they were stopping inaccurately, and that was after I took them up to a standardised version across the fleet. IIRC I took then to 37 something from various different versions and I now have everything on the same version which is currently 39 therefore I may not see the issue you describe?

[RFS]

3 hours ago, WIMorrison said:

This brings to mind a memory of a few locos needing reprofiling a while ago as they were stopping inaccurately, and that was after I took them up to a standardised version across the fleet. IIRC I took then to 37 something from various different versions and I now have everything on the same version which is currently 39 therefore I may not see the issue you describe?

 

Don't know when the change occurred. My MX600Rs were 31.63 and my MX634s 36.5 before I updated. Just need to be able to download again to see when the problem occurred.  I've looked through the Zimo changelogs and can see nothing relevant, but then this big change to CV5 that Stephan describes above is not mentioned either, hence my surprise that I had to reprofile all my Zimo locos. Fortunately that's only 10, as my other 75 all have Lenz decoders. 

 

Perhaps we need to continue this discussion on the other thread so things don't get duplicated?