Quick script to merge finetuned StabilityAI autoencoder into RunwayML Stable Diffusion 1.5 checkpoint

sd15_vae_merge.py

import torch

#USE AT YOUR OWN RISK

#local path to runwayML SD 1.5 checkpoint (https://huggingface.co/runwayml/stable-diffusion-v1-5)
ckpt_15 = "./v1-5-pruned-emaonly.ckpt"

#local path to StabilityAI finetuned autoencoder (https://huggingface.co/stabilityai/sd-vae-ft-mse)
ckpt_vae = "./vae-ft-mse-840000-ema-pruned.ckpt"

#path to save merged model to
ckpt_out = "./v1-5-pruned-emaonly_new_vae.ckpt"

pl_sd = torch.load(ckpt_15, map_location="cpu")
sd = pl_sd["state_dict"]

over_sd = torch.load(ckpt_vae,map_location="cpu")["state_dict"]

sdk = sd.keys()

for key in over_sd.keys():
    if "first_stage_model."+key in sdk:
        sd["first_stage_model."+key] = over_sd[key]        
        print(key,"overwritten")

torch.save(pl_sd,ckpt_out)

Hard to tell - I suspect you must either be using a wrong checkpoint or the checkpoints at the download locations have been changed.