Jason. You do know your stuff. Just like when I had an issue with my B1. You are very thorough in your explanations. Thanks Jason
Sooo, I want to try and flash this BIQU B1 back to the original firmware. I went to BIGTREETECH-SKR-V1.3/BTT SKR V1.4/Firmware/Marlin-bugfix-2.0.x-SKR-V1.4 at master · bigtreetech/BIGTREETECH-SKR-V1.3 · GitHub
I know this seems moronic but, I see a list of folders and files there, with no way to download and no instructions, and once again I am at a loss.
I would greatly appreciate any insight you can give. I know I need to get the firmware onto the card, insert it in the printer and start the printer. This really shouldn’t be this difficult. Or… maybe I am a moron. 
I think you need to be looking here:
You should be able to find prebuilt BIQU B1 firmware rather than have to build it yourself.
I don’t know - but I would say give it a try as it seems closer than anything else you have.
Unless you want to build the firmware yourself.
Ok, so I copied “FIRMWARE.BIN” to the freshly formatted sd card, put it in the motherboard slot, started the printer and the screen pretty much came on in the same amount of time as normal and looked normal. Only thing is, absolutely no reaction from any selection from the menu. So, I take the card back to the computer to maybe try a different one, but when I see the file on the card, it is now named “FIRMWARE.CUR”. Just to rule out it was something that I did, I repeated the whole procedure again with all the same results…??? Is this normal???
It sounds like you’re programming the Flash on the controller. I’m guessing you’re going to have to configure the LCD or load the LCD.bin files available there as well.
Hopefully, somebody with experience with this printer/controller can get you over the goal line.
There is usually a zip file of files required for the Lcd, If you need them you would remove the LCD from the printer, or if it’s accessible remove the bottom, Put the files on a freshly formatted SD Card, (card must have 4096-byte size) then put it in and start it up.
After flashing your firmware remember to select the “reset to default” setting. and then save settings.
Your previous one sounds like it worked.
Is there something specific that does not work? Can you home it, do you have heater control?
Jason
“Your previous one sounds like it worked.
Is there something specific that does not work? Can you home it, do you have heater control?”
I am not sure which previous one you are speaking of. When this whole thing started I had a fully functioning BIQU B1 with a bowden setup. I had attempted to flash the firmware with the new direct drive setup but there was never any indication that the firmware update happened.
After reverting everything back to the bowden setup is when I had the issue with the “C cable”. I replaced the cable, Hotend and circuit board with brand new ones, still the same “C cable” error.
I flashed it as suggested above and no more error, but the printer does not respond to any selections at all. I can navigate through all of the menus and even switch back and forth to Marlin, but that is it.
That pretty much is where I am at now.
But one thing no one has answered is, is it normal when you do a flash update for the process to rename your update file on the SD card to “FIRMWARE.CUR”?
Hi there
Yes, this is 100% normal, Its actually the last part of the “updating” process is to rename the file. It does this so that every time you boot your printer it does not reflash new firmware.
So it sounds like the firmware is installed but we need to define if the screen is talking to the mainboard. Consider them 2 different controllers that have to talk to each other.
It seems to me the mainboard is doing what it’s supposed to, ie, it flashed its own firmware which is a difficult thing to do, Next part is does the screen talk to the mainboard and get valid data from it.
I usually test this quickly by looking at the temp sensors on the screen and see if they both match within a deg of each other. They should both stateroom temp “21 deg”. Assuming you see similar temps on both the hot end and bed use a blow dryer and push hot air around the nozzle, as it warms up you should see the temp start to increase on the hot end reading on the screen. once it starts to move you can stop. Next, I would do the same thing to the bed, make sure the temp goes up and comes back down after the heat source is removed.
Assuming at this point either the screen is communicating or not, I am assuming at this point it is not, You will want to check your Baud settings on the screen and try all options until you find one that allows you to communicate with the mainboard. If you have exhausted all options from the screen I would suggest that you are able to connect pronterface via PC to your printer and we can do some additional testing there.
So after much trial and error, I finally got the touch screen updated, still, sadly nothing on the printer responds to touch screen input.
Nozzle and bed temp both show 0, just as before.
One odd thing I noticed, when I switch to Marlin mode, instead of the usual text menu, the only thing on the screen is the statement " BIQU B1 console" in green text.
I did some looking around - have you followed the procedures listed here:
https://www.reddit.com/r/BIGTREETECH/comments/q17yyk/biqu_b1_howto_upgrade_firmware/
It looks like you have to use two SD cards with one with the printer operations firmware and one with the LCD firmware with each placed in a different SD port.
I guess I will give that a try next, nothing to lose.
I see that I am not the only person that has come to the conclusion of how ridiculous this process is.
I agree, seems much more painful than it should be. Been a while since I have had a B1 here in the shop, Do not remember them being this much of a brute
I try not to modify my previous comments as If I say it I own it however after having lunch I may have sounded a little harsh above. Let me clarify a bit.
We have not had a B1 in the shop for service for a while and sometimes I forget the processes we have to go through to get them running/repaired. It kinda gets a little automated sometimes when you do it a lot.
I know I have to research all the new printers I see in store for the first time just to see if there are any gotchas on it. All printers can have their own little things that you need to be aware of them, Most of them have solutions posted.
In this case, it’s very much a non-standard issue with the conversion and the backing out of the firmware. Generally speaking, the manufacturers have documentation available on how to do the process and backing it up with some assistance from people like us is what I feel is the best way to learn stuff.
@ilistr8er not sure if you are local or not but we are always available to have a look at your printer for you and see if we can figure out whats going on with it.
Just wanted to reach out in case you may need some additional help.
I appreciate the offer, but I am in Oklahoma, if I remember from one of your earlier posts that is not near you.
OK, so I’m sorta getting somewhere, that is,… now I am almost back where I started.
So I did the two cards at the same time thing, now the printer is responsive again but nozzle temp shows -14/0, bed temp 21/0.
When I try homing, Z goes up a little, then down to limit then I get the “Please check whether the C-type line of the hotend is inserted”.
If I try to raise the nozzle temp I get the “Heating failed printer stopped” message, then “Printer halted Kill ( ) called”.
These are all the same messages and symptoms as before I started this whole firmware update thing. I have since replaced the hotend the C type wire and the board that they all plug into with brand new factory ones.
The hot end -14c indicates the thermister for the hot end is not connected or functioning I would check that from tip to tail and maybe swap it out if the wires are all ok, do you know if the new parts have the same kind of thermister as the old one?
I will check that as soon as I get home.
As far as the thermister being the same, it was a kit with the same parts as the original setup.