improve handling of pre-quantized flux

Signed-off-by: Vladimir Mandic <mandic00@live.com>

CHANGELOG.md

@@ -1,12 +1,13 @@
 # Change Log for SD.Next
 
-## Update for 2025-08-22
+## Update for 2025-08-23
 
 - **UI**  
   - improved image scaling in img2img and control interfaces  
 - **Fixes**
   - normalize path hanlding when deleting images  
   - fix hidden model tags in networks display  
+  - improve handling of pre-quantized flux models  
 
 ## Update for 2025-08-20
 

modules/sd_models.py

@@ -1157,13 +1157,18 @@ def unload_model_weights(op='model'):
         shared.log.debug(f'Unload {op}: {memory_stats()}')
 
 
-def hf_auth_check(checkpoint_info):
+def hf_auth_check(checkpoint_info, force:bool=False):
     login = None
-    try:
-        if (checkpoint_info.path.endswith('.safetensors') and os.path.isfile(checkpoint_info.path)) or (os.path.exists(checkpoint_info.path) and os.path.isdir(checkpoint_info.path) and os.path.isfile(os.path.join(checkpoint_info.path, 'model_index.json'))): # skip check for already downloaded models
-            return True
-    except Exception:
-        pass
+    if not force:
+        try:
+            # skip check for single-file safetensors models
+            if (checkpoint_info.path.endswith('.safetensors') and os.path.isfile(checkpoint_info.path)):
+                return True
+            # skip check for local diffusers folders
+            if (os.path.exists(checkpoint_info.path) and os.path.isdir(checkpoint_info.path) and os.path.isfile(os.path.join(checkpoint_info.path, 'model_index.json'))):
+                return True
+        except Exception:
+            pass
     try:
         login = modelloader.hf_login()
         repo_id = path_to_repo(checkpoint_info)

pipelines/model_flux.py

@@ -7,7 +7,7 @@ from pipelines import generic
 
 def load_flux(checkpoint_info, diffusers_load_config={}):
     repo_id = sd_models.path_to_repo(checkpoint_info)
-    sd_models.hf_auth_check(checkpoint_info)
+    sd_models.hf_auth_check(checkpoint_info, force=True)
 
     if 'Fill' in repo_id:
         cls_name = diffusers.FluxFillPipeline
@@ -38,13 +38,9 @@ def load_flux(checkpoint_info, diffusers_load_config={}):
     transformer = None
     text_encoder_2 = None
 
-    # handle transformer svdquant if available, t5 is handled inside load_text_encoder
-    prequantized = model_quant.get_quant(checkpoint_info.path)
-    if model_quant.check_nunchaku('Model'):
-        from pipelines.flux.flux_nunchaku import load_flux_nunchaku
-        transformer = load_flux_nunchaku(repo_id)
     # handle prequantized models
-    elif prequantized == 'nf4':
+    prequantized = model_quant.get_quant(checkpoint_info.path)
+    if prequantized == 'nf4':
         from pipelines.flux.flux_nf4 import load_flux_nf4
         transformer, text_encoder_2 = load_flux_nf4(checkpoint_info)
     elif prequantized == 'qint8' or prequantized == 'qint4':
@@ -54,6 +50,11 @@ def load_flux(checkpoint_info, diffusers_load_config={}):
         from pipelines.flux.flux_bnb import load_flux_bnb
         transformer = load_flux_bnb(checkpoint_info, diffusers_load_config)
 
+    # handle transformer svdquant if available, t5 is handled inside load_text_encoder
+    if transformer is None and model_quant.check_nunchaku('Model'):
+        from pipelines.flux.flux_nunchaku import load_flux_nunchaku
+        transformer = load_flux_nunchaku(repo_id)
+
     # finally load transformer and text encoder if not already loaded
     if transformer is None:
         transformer = generic.load_transformer(repo_id, cls_name=diffusers.FluxTransformer2DModel, load_config=diffusers_load_config)