BAFANG M420 FIRMWARE UPDATE

[werewolf14]

Hi guys,

some time ago i've change cassette in one of my clients bikes, bike brand is MAXBIKE and it was originally on 9speed cassette and my client wanted 11s. After upgrading bike throws 21 error, but only when riding on two biggest crowns. After consulting manufactuer of the bike i have beed told that their firmware supports max 42t on rear cassette. I own a BESST Tool account and adapter, but where to find firmware to update the engine (M420), or is there a parameter to change in the program?

 

[Neeko DeVinchi]

Error 21 is speed sensor abnormality on the Bafang system. Out of curiosity, I've looked through the 3 firmware options which I'm aware of concerning the m420 and none of them suggests that they alter the behaviour whereby gearing would influence the speed sensor spoke magnet.
I appreciate that you've installed an 11 speed cassette but the big question is, 'does the derailleur allow for the higher gear ratio?'
Looking at the bike's specs, it comes with a S-Ride M400 derailleur (10/11spd) with a capacity of 42t. Whilst you can get 11/42t cassettes for 11spd, I presume your client/customer wanted an 11/46t, 11/50t or 11/52t 11spd cassette. Please clarify if you've swapped out the derailleur and shifter. A shimano m5100 derailleur and shifter would be sufficient up to 11/50t. Also, has the chain link count been factored in to encompass the new wide range cassette?

My best guess (if you've completely swapped the drivetrain), is that the rear wheel spoke magnet sensor is not positioned on a spoke which is farthest outboard depending on the spoke lacing pattern. Therefore, repositioning the spoke sensor to a different spoke (or using a spacer to bridge the gap of the speed sensor away from the none driveside chainstay), could eliminate the issue.

Failing all this, I'll have a word with one of my contacts who will be able to source you the different firmwares of the m420. I presume you have the besst tool and an account with Bafang?

 

[werewolf14]

Error 21 is speed sensor abnormality on the Bafang system. Out of curiosity, I've looked through the 3 firmware options which I'm aware of concerning the m420 and none of them suggests that they alter the behaviour whereby gearing would influence the speed sensor spoke magnet.
I appreciate that you've installed an 11 speed cassette but the big question is, 'does the derailleur allow for the higher gear ratio?'
Looking at the bike's specs, it comes with a S-Ride M400 derailleur (10/11spd) with a capacity of 42t. Whilst you can get 11/42t cassettes for 11spd, I presume your client/customer wanted an 11/46t, 11/50t or 11/52t 11spd cassette. Please clarify if you've swapped out the derailleur and shifter. A shimano m5100 derailleur and shifter would be sufficient up to 11/50t. Also, has the chain link count been factored in to encompass the new wide range cassette?

My best guess (if you've completely swapped the drivetrain), is that the rear wheel spoke magnet sensor is not positioned on a spoke which is farthest outboard depending on the spoke lacing pattern. Therefore, repositioning the spoke sensor to a different spoke (or using a spacer to bridge the gap of the speed sensor away from the none driveside chainstay), could eliminate the issue.

Failing all this, I'll have a word with one of my contacts who will be able to source you the different firmwares of the m420. I presume you have the besst tool and an account with Bafang?

Thank you very much for your reply. On my client bike there was 9s casette with 11-36t. I have changed it to 11-50t 11speed cassette. Speed senspor was my first thought, but it seems to be ok, especially that the bike works on crowns form 1-9 but speed sensor fault shows only on the two biggest crowns. Chain length schould be ok too.
Manufactuer of the bike tells me that their firmware works only up to 42t.

Yes, i have Besst Tool with working account.

 

[vikino1]

In another forum, it was solved like this, but M400 ... It's actually solvable, with the older M400 up to 42T it works without any problems.... When you go to 46-50T, there is jerking in the engine and speed sensor error 21... The solution is 2 magnets, and changing to 2 sensors, you can do it at home as long as you have a round 5pin + usb uart connection. Bafang for the m400 and more tooth cartridge solved it with new software...just replace, upload new software. By the way, improve the purchased bike, by changing the cassette, improving... When they are not enough for you, e.g. Slx derailleur or you switch to higher brakes on XT or even xtr so it's perfectly fine.... The thinking is, if I have a bike for the price, and suddenly I found out that I need a better, new one... why just buy a new bike , when only the brakes are enough... And that's exactly with the cassette, engine... unlocking... Etc... 20.03.2021 - 19:29:31 00

 

[manuroup]

Error 21 is speed sensor abnormality on the Bafang system. Out of curiosity, I've looked through the 3 firmware options which I'm aware of concerning the m420 and none of them suggests that they alter the behaviour whereby gearing would influence the speed sensor spoke magnet.
I appreciate that you've installed an 11 speed cassette but the big question is, 'does the derailleur allow for the higher gear ratio?'
Looking at the bike's specs, it comes with a S-Ride M400 derailleur (10/11spd) with a capacity of 42t. Whilst you can get 11/42t cassettes for 11spd, I presume your client/customer wanted an 11/46t, 11/50t or 11/52t 11spd cassette. Please clarify if you've swapped out the derailleur and shifter. A shimano m5100 derailleur and shifter would be sufficient up to 11/50t. Also, has the chain link count been factored in to encompass the new wide range cassette?

My best guess (if you've completely swapped the drivetrain), is that the rear wheel spoke magnet sensor is not positioned on a spoke which is farthest outboard depending on the spoke lacing pattern. Therefore, repositioning the spoke sensor to a different spoke (or using a spacer to bridge the gap of the speed sensor away from the none driveside chainstay), could eliminate the issue.

Failing all this, I'll have a word with one of my contacts who will be able to source you the different firmwares of the m420. I presume you have the besst tool and an account with Bafang?

HI, I've a M420 bafang motor, and I'm looking for firmware for Canbus M420 controler 43 volts . I have to replace controler but only 36Volts is selling . If I buy besst tool , I could update new 36V controler to 43V ?
Do you have this firmware ?

 

[Neeko DeVinchi]

HI, I've a M420 bafang motor, and I'm looking for firmware for Canbus M420 controler 43 volts . I have to replace controler but only 36Volts is selling . If I buy besst tool , I could update new 36V controler to 43V ?
Do you have this firmware ?

Hi there,
Sincere apologies for the delay (work commitments).
Please bare with me. It would be easier for me to get my colleague to forward the 43v firmware to you or share it to this thread.

If I anticipate a delay in my colleague doing this, I'll step in and share it to this thread

 

[manuroup]

Hi ,
Yes exaclty, I would like to get this firmware, last one FC. 3.0 if possible for CRX10V.350 controller (or previous xxx. FC.2.0 / FC.1.0)