Anycubic Photon 5.5 3D printer 25Q32 flashrom dump needed

[re-atari]

Hello all, as the title says, I'm very much in need of a valid firmware dump of a Anycubic Photon 5.5 3D resin printer. It's stored in a Winbond 25Q32, so it's 4Mbyte.

Here's a little background for my request. A few weeks ago I bought this 3D printer from a guy who had moved on to a PLA printer. I got it at a vey reasonable price, as it was in a defective state. The seller told me that he had experienced a power failure during a firmware upgrade, after which the printer appeared to be dead. He thought the firmware was corrupted in such a way that the printer was now bricked. As he found the Photon's printable area to small anyway, he had decided to sell it and move on to a larger 3D printer.

As I like a challenge, I decided to have a go at trying to fix the Photon. When I got to tinker with it, the printer indeed seemed to be completely bricked. So much so, that after switching on the device does exactly nothing, the touchscreen on the front stays black, no audible beeps and the fan does not spin up. I can see a red led light on the mainboard lighting up.

I already did some research, and found a few pages on Reddit describing how to debrick this printer:
https://www.reddit.com/r/resinprinti...th_a_chitubox/
and
https://www.reddit.com/r/AnycubicPho...ton_s_after_a/

In short, you switch the device on with a specially prepared USB stick inserted, which should then force a firmware flashback. Sadly that method did not work. I did see the activity light on the USB stick flash in regular intervals (I think 1x per second?), so something seems to be working on the mainboard. After a few minutes I decided it was not going to work and stopped.

I then removed the mainboard, and did a visual inspection and took some measurements, but could not find any defective components. It's possible the STM32F407's bootloader is damaged, good luck restoring that... So I tried to read out the flashrom with my eprom programmer and 8 pin IC clip, but sadly could not put the clip on the flashrom as there is a piezo beeper placed too close by. So, the beeper will have to be unsoldered first.

I still need a known good dump of the flashrom, though. First to compare the contents of the 2 dumps, and second to flash the known good dump back. Therefore, I'd appreciate it very much if anyone in possession of a known good flashrom dump for the Anycubic Photon would be so kind to upload it here. The mainboard is a Chitu L V1 v.2.9, see attached photo's.

Thanx in advance!

[re-atari]

4 weeks went by without anyone chiming in. So, I had another go at trying to bring my Photon printer back to life myself, and now I did succeed! I followed the tutorials on how to debrick the device that I linked to in my opening post, but with a small yet quite essential difference.

This time I used another USB stick to force a firmware flashback, and all in all it took only a minute or so to debrick the printer. I found out the hard way you MUST use a FAT32 formatted USB stick, any other format will not be detected by the printer. Four weeks ago I used an old small capacity (32Mb, was more than large enough) FAT-formatted USB stick, which was simply not detected. This time I took a Kingston 4GB stick which I slow-formatted in FAT32 before copying the 2 firmware recovery files (v.4.2.19) and script on it.

After switching the printer on, the USB stick was immediately recognized, the fan started spinning and the front display came to life. That was already way more than the printer had done up to now. It complained that the firmware on the USB stick (v.4.2.19) was already installed, though, so would not update this, and then showed a display with a progress bar about updating the LCD firmware. The bar just stayed at 1% for a few minutes. After realizing it was simply waiting for my input, I pressed the 'play' button, after which it really flew through the rest of the update. Took less than 10 seconds in all. I switched the printer off and after a few seconds back on again, to find it was now fully functional. I immediately did a Z-height calibration, which went perfectly fine. So, it looks like fixing my printer was succesful.

I did not have a go yet at desoldering the piezo beeper in order to dump the complete flashrom contents using an IC clip, if only for posterity. I'm reluctant to take the PCB out again, as one of the connectors (J6 on the above photo) is very fiddly to reconnect properly. So, I will skip dumping the flashrom for now. No need to break the printer again after fixing it.

Lastly, I would like to thank the authors of both of the above mentioned tutorials on how to debrick Photon printers. Without their insight, the previous owner of my now functional again printer would probably have thrown it in the dumpster.