diff --git a/kohya_gui/class_flux1.py b/kohya_gui/class_flux1.py
index e9ec461d..fc2d7b17 100644
--- a/kohya_gui/class_flux1.py
+++ b/kohya_gui/class_flux1.py
@@ -176,7 +176,7 @@ def noise_offset_type_change(
                     self.blockwise_fused_optimizers = gr.Checkbox(
                         label="Blockwise Fused Optimizer",
                         value=self.config.get("flux1.blockwise_fused_optimizers", False),
-                        info="Enable blockwise optimizers for fused backward pass and optimizer step",
+                        info="Enable blockwise optimizers for fused backward pass and optimizer step. Any optimizer can be used.",
                         interactive=True,
                     )
                     self.cpu_offload_checkpointing = gr.Checkbox(
@@ -203,6 +203,12 @@ def noise_offset_type_change(
                         step=1,
                         interactive=True,
                     )
+                    self.flux_fused_backward_pass = gr.Checkbox(
+                        label="Fused Backward Pass",
+                        value=self.config.get("flux1.fused_backward_pass", False),
+                        info="Enables the fusing of the optimizer step into the backward pass for each parameter.  Only Adafactor optimizer is supported.",
+                        interactive=True,
+                    )
 
                 self.flux1_checkbox.change(
                     lambda flux1_checkbox: gr.Accordion(visible=flux1_checkbox),
diff --git a/kohya_gui/dreambooth_gui.py b/kohya_gui/dreambooth_gui.py
index 09681cc6..169d9834 100644
--- a/kohya_gui/dreambooth_gui.py
+++ b/kohya_gui/dreambooth_gui.py
@@ -222,6 +222,7 @@ def save_configuration(
     t5xxl_max_token_length,
     guidance_scale,
     blockwise_fused_optimizers,
+    flux_fused_backward_pass,
     cpu_offload_checkpointing,
     single_blocks_to_swap,
     double_blocks_to_swap,
@@ -424,6 +425,7 @@ def open_configuration(
     t5xxl_max_token_length,
     guidance_scale,
     blockwise_fused_optimizers,
+    flux_fused_backward_pass,
     cpu_offload_checkpointing,
     single_blocks_to_swap,
     double_blocks_to_swap,
@@ -621,6 +623,7 @@ def train_model(
     t5xxl_max_token_length,
     guidance_scale,
     blockwise_fused_optimizers,
+    flux_fused_backward_pass,
     cpu_offload_checkpointing,
     single_blocks_to_swap,
     double_blocks_to_swap,
@@ -902,7 +905,7 @@ def train_model(
         "fp8_base": fp8_base,
         "full_bf16": full_bf16,
         "full_fp16": full_fp16,
-        "fused_backward_pass": fused_backward_pass,
+        "fused_backward_pass": fused_backward_pass if not flux1_checkbox else flux_fused_backward_pass,
         "fused_optimizer_groups": (
             int(fused_optimizer_groups) if fused_optimizer_groups > 0 else None
         ),
@@ -1053,6 +1056,7 @@ def train_model(
         "blockwise_fused_optimizers": (
             blockwise_fused_optimizers if flux1_checkbox else None
         ),
+        # "flux_fused_backward_pass": see previous assignment of fused_backward_pass in above code
         "cpu_offload_checkpointing": (
             cpu_offload_checkpointing if flux1_checkbox else None
         ),
@@ -1399,6 +1403,7 @@ def dreambooth_tab(
             flux1_training.t5xxl_max_token_length,
             flux1_training.guidance_scale,
             flux1_training.blockwise_fused_optimizers,
+            flux1_training.flux_fused_backward_pass,
             flux1_training.cpu_offload_checkpointing,
             flux1_training.single_blocks_to_swap,
             flux1_training.double_blocks_to_swap,
diff --git a/kohya_gui/finetune_gui.py b/kohya_gui/finetune_gui.py
index 0b51186a..b8e61471 100644
--- a/kohya_gui/finetune_gui.py
+++ b/kohya_gui/finetune_gui.py
@@ -230,6 +230,7 @@ def save_configuration(
     t5xxl_max_token_length,
     guidance_scale,
     blockwise_fused_optimizers,
+    flux_fused_backward_pass,
     cpu_offload_checkpointing,
     single_blocks_to_swap,
     double_blocks_to_swap,
@@ -438,6 +439,7 @@ def open_configuration(
     t5xxl_max_token_length,
     guidance_scale,
     blockwise_fused_optimizers,
+    flux_fused_backward_pass,
     cpu_offload_checkpointing,
     single_blocks_to_swap,
     double_blocks_to_swap,
@@ -652,6 +654,7 @@ def train_model(
     t5xxl_max_token_length,
     guidance_scale,
     blockwise_fused_optimizers,
+    flux_fused_backward_pass,
     cpu_offload_checkpointing,
     single_blocks_to_swap,
     double_blocks_to_swap,
@@ -954,7 +957,7 @@ def train_model(
         "fp8_base": fp8_base,
         "full_bf16": full_bf16,
         "full_fp16": full_fp16,
-        "fused_backward_pass": fused_backward_pass,
+        "fused_backward_pass": fused_backward_pass if not flux1_checkbox else flux_fused_backward_pass,
         "fused_optimizer_groups": (
             int(fused_optimizer_groups) if fused_optimizer_groups > 0 else None
         ),
@@ -1097,6 +1100,7 @@ def train_model(
         "blockwise_fused_optimizers": (
             blockwise_fused_optimizers if flux1_checkbox else None
         ),
+        # "flux_fused_backward_pass": see previous assignment of fused_backward_pass in above code
         "cpu_offload_checkpointing": (
             cpu_offload_checkpointing if flux1_checkbox else None
         ),
@@ -1517,6 +1521,7 @@ def list_presets(path):
             flux1_training.t5xxl_max_token_length,
             flux1_training.guidance_scale,
             flux1_training.blockwise_fused_optimizers,
+            flux1_training.flux_fused_backward_pass,
             flux1_training.cpu_offload_checkpointing,
             flux1_training.single_blocks_to_swap,
             flux1_training.double_blocks_to_swap,
diff --git a/sd-scripts b/sd-scripts
index 2b07a92c..e1cd19c0 160000
--- a/sd-scripts
+++ b/sd-scripts
@@ -1 +1 @@
-Subproject commit 2b07a92c8d970a8538a47dd1bcad3122da4e195a
+Subproject commit e1cd19c0c0ef55709e8eb1e5babe25045f65031f