Hi Coulomb!
I did the file renaming and since then my inverter is a brick!
Easun smw 8kw.
I updated the factory firmware from the voltronic ftp page: MAX_8K_28066_9204.7Z
After that, based on your description, I renamed dsp.hex vp5k and flashed it. My inverter has been a brick ever since. I tried everything, removed the display, but it didn't work! Can you give me some advice? Sorry for my English google translator! I'm Hungarian. Please help!