If you hadn’t said it was the same spool, I would have guessed that the bottom print was from a spool that needed drying. It sure looks like signature filament wetness. Well, only you would know.
Not likely to work as a drop-in. With a new nozzle, I expect you may need to go through the whole filament dial-in process using calibration models. Well, the good news is that on the H2D, you don’t have to for pressure advance (because the automatic calibration for that seems to work pretty well–just remember to turn it ON after slicing and just prior to sending your print to the H2D by selecting it under Print Options in the dialog box), but you still need to for, at minimum flow rate (which, you’re in luck the H2D Bambu slicer provides a manual calibration tool for you to use), but also maximum flow rate (not in luck. you’ll have to find something on makerworld–I found one that worked for PLA but the same author’s PETG version didn’t seem to work on the H2D, IIRC), temperature tower (also not in luck. Current state of the art seems to be this:
). You might also need a different dial-in for first layer PETG on H2D: I’m in the middle of figuring that one out myself. AFAIK, the Bambu H2D slicer allows for this first layer difference, but I haven’t yet tested that aspect of it.
And that’s just for starters. Then you’ll need to dial-in a custom process profile for your 0.8mm nozzle if you want to get the most out of it. For that, others will need to advise.
I’m not defending the status quo, just explaining it as best I understand it. I’m not a know-it-all by any means, and I hope I don’t come across that way. I’m just trying to be helpful.
If anyone has a contrary or otherwise different point of view, please do post it. And if I’m flat out wrong, please do call me on it. We’re all swimming in the same pool, and so maybe we can help each other out by sharing whatever methods/techniques we’ve learned/adopted that seem to work well with dialing in a new filament or nozzle on H2D. I like that @Michael4 isn’t afraid to push the envelope and thereby help blaze the trail. Since that benefits all of us, we should do our best to support his attempt. In return, I hope @Michael4 will at least report back what does or doesn’t work as his minimum quid pro quo, as that’s not really asking much.
Anyhow, I’ve so far gotten good results dialing in a new HS-PLA filament, despite the obstacles, and I’m part-way through dialing in a new HS-PETG filament:
Both are 0.4mm nozzles. I wasn’t aware that Bambu even had the other nozzle sizes available yet, so good on ya for getting yours already.