Tarek Yag

I just finished some experimenting with firmware on my VM IV Twin, and it just came to my attention that Voltronic started using a slightly different naming convention for firmware packages intended for use with the TWIN variants. Packages now are named "VM TWIN" with no indication whether it is for VM III or VM IV. At first, I thought it was missing the complete name by mistake, but as I re-downloaded all the packages again now, I made sure that it is not by mistake. Moreover, the instructions document inside each package named "VM TWIN" now says "VM III and IV" in its title at first line. So, I believe they're indicating now that they're interchangeable for both models of the Twin variant. @Coulomb, what do you think?

You can refer to another post of mine where I attached the latest communication protocol I'm aware of. It might be of a big help for your project. Additionally, you can find other documents using the search tool and the files section as @Coulomb just stated two posts before this post. My other post link: https://powerforum.co.za/topic/19010-voltronic-axpert-vm-iii-twin-4kw/?do=findComment&comment=205780 You can refer to this post too: https://powerforum.co.za/topic/21234-axpert-vm-iv-twin-firmware-request/?do=findComment&comment=205765 From my perspective as a Software Engineer, I'd always recommend using the latest available firmware. I'd never expect any good enough or valid information from these amateur teams!

Yeah, totally understood! We all love tweaking with inverters 😁 So, how did you manage to make them give you more details? I've tried once to ask for a firmware update but they refused to give any details! I also reported to Eybond about a few bugs in the inverter's monitoring system (DessMonitor), and asked for a firmware update for the Wi-Fi kit, but got no useful help at all!

So I'm assuming you're one of their OEM clients selling under a specific brand? Because they always refuse to talk to end consumers.

I've never heard of a firmware change log for Voltronic inverters, though Coulomb is always interested in making version comparisons when needed. Since there are no change logs, improvements are not documented, hence not guaranteed! I salute you for conquering your curiosity! 😂

@pintopf Great news! Thanks for your feedback. Any plans to upgrade your display firmware?

In the unexpected case of overwriting the bootloader of my VM IV Twin inverter, is there any way to fix it without replacing hardware?

No one explicitly said that they tried 60.95 in this thread neither mhd_murad. Quieter fans are introduced in several recent VM III firmware versions as testers mentioned in this thread. @mhd_murad would you please confirm which DSP firmware you had the incompatibility with?

It's my pleasure to pay back for your efforts and help! Nothing else to be added, you covered it perfectly. Try it yourself next time you get to reflash an inverter with a micro-USB port. I can't think of a possibility other than it is hard coded in the reflash app, hence making it work for specific models only with the same DSP addresses. I will try flashing my inverter's DSP using the MCU reflash tool while sniffing the serial connection to see what will be going on. I'll try to do it in the next couple of days and post any updates here. Do you think it could overwrite the bootloader by any means?

Thank you very much! I really appreciate it.

Yeah, it was a wild idea trying to match with a wild thing! I'm very skeptical about the possibility too.

That's exactly what I expected in my previous post. I hope everything should be fine now.

I'm afraid you got told inaccurate or false information. With a quick thinking, the only easy way (a shortcut) that came to my mind is to use a DC-DC step-down circuit to lower battery voltage from 48 to 24. I don't know, but anyways it's a completely wrong practice.

No, he tried a lot of firmware versions, looks like this is one of his attemps and is very old. He is supposed to flash 70.00 right now as he has VM IV Twin just like me. Would you please provide more details about the components of this cable?

Oh, sorry to hear this! I'm afraid it has become some sort of incompatibility between MCU and DSP firmware, although I think no one can confirm it. Would he like to try and reflash his DSP firmware too? So he reflashes both DSP and MCU to their latest versions. @Coulomb any thoughts?

LOL, there you go now! 😂 Even I found it by luck last year while messing around with the selection after failing COM port attemps in my very first DSP reflash! I would like to suggest that you update your reflash instructions to reflect the existence of the USB option I mentioned above. Are you sure there are any INI files included in the MCU reflash tool? I never noticed this. How can we make sure of this? You know, I'm always ready to reflash firmware, and I'm ready for a challenge now as long as it doesn't render my inverter completely bricked! It should be ok as long as I can reflash with the known tools.

Exactly, you're right on track! I Wish you good luck with this. I understand that it's very confusing at the beginning, but once you do it the first time it becomes an easy task.

Sorry, but you totally forgot to include the link Exactly! Totally on point, I was going to tell him the same thing, but you were quicker than me. Sorry for the confusion, I should have included the link for DSP and MCU reflash instructions posted by Coulomb since the beginning, to provide you with all the details you needed so you didn't need to ask for more details each time. It just came to my attention that I didn't include the link in the first post of this thread too, so I just included it now. Here's the link for your convenience: https://forums.aeva.asn.au/viewtopic.php?p=87767#p87767

It does, I was never able to reflash my DSP firmware using my USB to RS232 adapter, although I tried different ones with Prolific and FTDI chips!! The USB port is selectable right above COM1 in the reflash tool. It is indeed. However, you never have to specify the baud rate in Windows as it communicates with the inverter using USB FS Mode (Full Speed) protocol as a HID device. This way, you don't have to worry about a lot of driver settings, thus much easier process, and at the same time, stay away of all the well-known hassles around USB to Serial adapters, thus cutting down costs. This is my case indeed. I reflashed my inverter's DSP more than 10 times since last year using USB only, and was never able to do so using my adapters as I tried tens of times. Moreover, I did a very extensive research and a lot of experiments in USB to Serial (both RS232 and RS485) issues over a period of two weeks about a month ago. I found out some important details about a few problematic aspects in this regard. I will be opening a separate thread to discuss about it all in this forum, and I'm very interested to discuss it with you specifically, @Coulomb By the way, do you think it is possible to make this DSP reflash tool to be able to reflash MCU firmware by editing InvConfigFile.ini file to reflect MCU ROM addresses?

Don't worry man, you're good! You can't really return to the exact stock firmware that came with the device, as it is (not possible) to extract it or make a backup of it. However, you can reflash the very same firmware version and it should be all good and no differences. As a general rule, you can always reflash whatever firmware version you like, as long as it is exactly for your device's model. There are no version restrictions when it comes to reflashing a firmware. You can use the search feature in this forum to find other MCU firmware versions. There are a lot of options if anything would go wrong for you, and I guess you'll find the exact version or a very close one at least. Just always make sure you know what you're searching for!

Yep, according to your image, your inverter is from a well-known brand in the region, and it should be an original one. Yeah, MCU firmware, display firmware, and secondary CPU firmware, all refer to the same thing. And no, the reflash tool for MCU firmware (secondary CPU) is totally different than the reflash tool for DSP firmware (main CPU). The tool for the MCU firmware is already included in the zipped file uploaded here by mhd_murad along with the firmware file (25.12) As for the reflash tool for DSP firmware, I have it attached in the first post.

@mohamed.kh According to your current firmware versions and the aforementioned inverter model (VM III Twin)... You might want to test one of the three recent DSP firmware. Versions 60.89, 60.95, or 68.04. They're all attached in this thread in different posts with some basic first impression of testers about each of them, as they're not very much tested, yet. As for the MCU (display) firmware, the latest firmware I'm aware of is 25.12, and is also attached in this thread.

I could provide you with more relevant and quicker assistance if you could provide me a picture of your inverter's sticker, as this should make things much easier for us. I suspect that you're not using the suitable firmware for your inverter's model.

@waaalid flash your DSP firmware over USB, not serial, using the same flash tool, and everything will go smooth. If not, try flashing using OTG. This should complete your upgrade nice and easy!

Exactly right! This is a perfect setup! Totally expected and normal, you nailed the perfect numbers already! Good for you. You don't need to get any higher than the nominal MPPT voltage, you're already in the perfect range.