Inconsistent results (aka failures) burning Repetier 92.9 firmware

[T02900]

Hi. I'm in the process of attempting to replace the manufacturer provided Repetier .91 (on a P802M type printer) with 92.9. I'm seeing inconsistent results (to say the least).

First, I used avrdude to read out the current firmware as a hex file protection copy. No problems there.

I obtained a Configuration.h that is purported to be correct for this unit and board (and appears correct on inspection) -- ran it through the Repetier Configurator, downloaded the result, compiled with latest Arduino and exported hex OK (both with and without bootloader versions).

I used avrdude to try write the new version (without bootloader). It appeared successful -- wrote and verified without errors. However, it doesn't boot -- the display just shows the two blank lines on the four line display that is typical at the start of the booting procedure.

I then tried to write back the original downloaded firmware (.91). The write went OK, but avrdude exited before verifying. However, the firmware appears intact and the unit is booting and (in quick tests) seems functional -- with the original .91 firmware again.

I tried uploading the new version once again, but this is when things got stranger. Avrdude goes through its write cycle, the verify cycle, and then complains of a verify error. This is now consistent, and I stopped for now.

So at this time, I'm apparently back with the original .91 firmware and momentarily stuck.

I've seen some discussions suggesting a bootloader issue relating to .92 and I do have the new 92.9 hex file with the bootloader -- but I'm reluctant to burn that one without really understanding what's going on since I don't want to brick the unit completely.

Any suggestions appreciated. Thanks very much!

[Eric]

P802M is a chinese take on the Prusa, right? Presumably with some chinese version of the electronics.

I'm sure you lost the bulk of this forums readers with the direct use of avrdude. Most let the Arduino IDE handle that for them. What's the address given when you get verify errors? Is it always the same address? What's the image size you're trying to write?

Seeme currently delivers a significantly customized branch of Repetier 92.2 configured for delta machines, so I suspect VERY few people that read this forum are in a position to duplicate your issue. I've seen no discussions about bootloader issues of the type you mention, at least not in this forum.

[T02900]

I'll dig into this more and report back. Thanks for your reply!

[T02900]

More info on this. I can (apparently) successfully upload AND get a good verification on the original firmware dump that I downloaded from the printer originally. However, when I try to upload the newer firmware (about 20K smaller, which is a bit suspicious but we'll let that pass for now) it always gets a verify error on 0x0002.

In some instances, I've had to power cycle printer to get the upload phase to work, that is, before pressing reset on the board and starting avrdude.

So to review, the original firmware (.91) uploads and verify succeeds. The new firmware (.92.9) uploads and the verify fails.

Thanks.

[T02900]

One possibility: It's not really erasing or uploading at all. In fact, I have evidence that it actually hasn't erased (though signature checks are good, and the fuses read back as good). But if no erase or flash is really taking place, then that would explain why when I "uploaded" the original firmware back the verify succeeds -- because it's been there all along! Attempts to upload the new firmware verify against the original firmware still in there, and so the verify fails. Feasible? But this doesn't really point at a solution yet.