diff --git a/tests/saving/gpt-oss-merge/run_test.sh b/tests/saving/gpt-oss-merge/run_test.sh
new file mode 100755
index 0000000000..5a91b31358
--- /dev/null
+++ b/tests/saving/gpt-oss-merge/run_test.sh
@@ -0,0 +1,18 @@
+#!/bin/bash
+set -e
+
+echo "================================================================"
+echo "🚀 STEP 1: Running the training and merging script..."
+echo "================================================================"
+python train_and_merge.py
+
+echo ""
+echo "================================================================"
+echo "✅ STEP 2: Training complete. Running the inference script..."
+echo "================================================================"
+python test_merged_model.py
+
+echo ""
+echo "================================================================"
+echo "🎉 All steps completed successfully!"
+echo "================================================================"
diff --git a/tests/saving/gpt-oss-merge/test_merged_model.py b/tests/saving/gpt-oss-merge/test_merged_model.py
new file mode 100644
index 0000000000..c13a941fb7
--- /dev/null
+++ b/tests/saving/gpt-oss-merge/test_merged_model.py
@@ -0,0 +1,55 @@
+# inference_on_merged.py
+from unsloth import FastLanguageModel
+from transformers import TextStreamer
+import torch
+import gc
+import os
+import shutil
+
+def safe_remove_directory(path):
+    try:
+        if os.path.exists(path) and os.path.isdir(path):
+            shutil.rmtree(path)
+            return True
+        else:
+            print(f"Path {path} is not a valid directory")
+            return False
+    except Exception as e:
+        print(f"Failed to remove directory {path}: {e}")
+        return False
+pass
+
+print("🔥 Loading the 16-bit merged model from disk...")
+merged_model, merged_tokenizer = FastLanguageModel.from_pretrained(
+    model_name="./gpt-oss-finetuned-merged",
+    max_seq_length=1024,
+    load_in_4bit=True,
+    load_in_8bit=False,
+)
+print("✅ Merged model loaded successfully.")
+
+# --- Run Inference ---
+print("\n🚀 Running inference...")
+messages = [
+    {"role": "user", "content": "Solve x^5 + 3x^4 - 10 = 3."},
+]
+inputs = merged_tokenizer.apply_chat_template(
+    messages,
+    add_generation_prompt = True,
+    return_tensors = "pt",
+    return_dict = True,
+    reasoning_effort = "low", # **NEW!** Set reasoning effort to low, medium or high
+).to(merged_model.device)
+
+_ = merged_model.generate(**inputs, max_new_tokens = 512, streamer = TextStreamer(merged_tokenizer))
+print("\n✅ Inference complete.")
+
+# --- Final Cleanup ---
+print("\n🧹 Cleaning up merged model directory and cache...")
+del merged_model, merged_tokenizer
+torch.cuda.empty_cache()
+gc.collect()
+
+safe_remove_directory("./gpt-oss-finetuned-merged")
+safe_remove_directory("./unsloth_compiled_cache") # Clean up cache created by this process
+print("✅ Final cleanup complete. Exiting inference script.")
diff --git a/tests/saving/gpt-oss-merge/train_and_merge.py b/tests/saving/gpt-oss-merge/train_and_merge.py
new file mode 100644
index 0000000000..b242dbc58b
--- /dev/null
+++ b/tests/saving/gpt-oss-merge/train_and_merge.py
@@ -0,0 +1,71 @@
+# train_and_merge.py
+from unsloth import FastLanguageModel
+from trl import SFTTrainer, SFTConfig
+from datasets import load_dataset
+import torch
+import gc
+import os
+import shutil
+
+def safe_remove_directory(path):
+    try:
+        if os.path.exists(path) and os.path.isdir(path):
+            shutil.rmtree(path)
+            return True
+        else:
+            print(f"Path {path} is not a valid directory")
+            return False
+    except Exception as e:
+        print(f"Failed to remove directory {path}: {e}")
+        return False
+pass
+
+# This tokenizer will be used by the mapping function
+tokenizer = None
+def formatting_prompts_func(examples):
+    convos = examples["messages"]
+    texts = [tokenizer.apply_chat_template(convo, tokenize=False, add_generation_prompt=False) for convo in convos]
+    return {"text": texts}
+
+# --- Load 4-bit Model and Train ---
+print("Loading 4-bit Mxfp4 gpt-oss model for training...")
+max_seq_length = 1024
+model, tokenizer = FastLanguageModel.from_pretrained(
+    "unsloth/gpt-oss-20b", max_seq_length=max_seq_length, load_in_4bit=True
+)
+
+dataset = load_dataset("HuggingFaceH4/Multilingual-Thinking", split="train[:50]").map(
+    formatting_prompts_func, batched=True
+)
+
+model = FastLanguageModel.get_peft_model(
+    model, r=8, target_modules=["q_proj", "k_proj", "v_proj", "o_proj", "gate_proj", "up_proj", "down_proj"],
+    lora_alpha=16, use_gradient_checkpointing="unsloth", random_state=3407,
+)
+
+trainer = SFTTrainer(
+    model=model, tokenizer=tokenizer, train_dataset=dataset,
+    args=SFTConfig(
+        per_device_train_batch_size=1, gradient_accumulation_steps=4, max_steps=10,
+        learning_rate=2e-4, output_dir="outputs", report_to="none",
+    ),
+)
+
+print("Starting fine-tuning...")
+trainer.train()
+print("Fine-tuning complete.")
+
+# --- Merge and Save ---
+print("\n💾 Merging and saving the 16-bit model to './gpt-oss-finetuned-merged'...")
+model.save_pretrained_merged(save_directory="./gpt-oss-finetuned-merged", tokenizer=tokenizer)
+print("✅ Model merged and saved.")
+
+# --- Cleanup ---
+print("\n🧹 Cleaning up training artifacts...")
+del model, trainer, tokenizer, dataset
+torch.cuda.empty_cache()
+gc.collect()
+
+safe_remove_directory("./outputs")
+safe_remove_directory("./unsloth_compiled_cache") # Clean up the cache created by this process
+print("✅ Cleanup complete. Exiting training script.")
diff --git a/tests/saving/language_models/test_merge_4bit_validation.py b/tests/saving/language_models/test_merge_4bit_validation.py
new file mode 100644
index 0000000000..b135e52454
--- /dev/null
+++ b/tests/saving/language_models/test_merge_4bit_validation.py
@@ -0,0 +1,223 @@
+from unsloth import FastLanguageModel
+from unsloth.chat_templates import get_chat_template
+from trl import SFTTrainer, SFTConfig
+from transformers import DataCollatorForSeq2Seq, TrainingArguments
+from datasets import load_dataset
+import torch
+import sys
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).parents[3]
+sys.path.insert(0, str(REPO_ROOT))
+
+from tests.utils.cleanup_utils import safe_remove_directory
+
+def formatting_prompts_func(examples):
+    convos = examples["messages"]
+    texts = [tokenizer.apply_chat_template(convo, tokenize=False, add_generation_prompt=False) for convo in convos]
+    return {"text": texts}
+
+print(f"\n{'='*80}")
+print("🔍 PHASE 1: Loading Base Model and Initial Training")
+print(f"{'='*80}")
+
+if torch.cuda.is_bf16_supported():
+    compute_dtype = torch.bfloat16
+    attn_implementation = 'flash_attention_2'
+else:
+    compute_dtype = torch.float16
+    attn_implementation = 'sdpa'
+
+model, tokenizer = FastLanguageModel.from_pretrained(
+    model_name="unsloth/Llama-3.1-8B-Instruct",
+    max_seq_length=2048,
+    dtype=compute_dtype,
+    load_in_4bit=True,
+    load_in_8bit=False,
+    full_finetuning=False,
+    attn_implementation=attn_implementation
+)
+
+tokenizer = get_chat_template(
+    tokenizer,
+    chat_template="llama-3.1",
+)
+
+# Load small dataset for quick training
+dataset_train = load_dataset("allenai/openassistant-guanaco-reformatted", split="train[:100]")
+dataset_train = dataset_train.map(formatting_prompts_func, batched=True)
+
+print("✅ Base model loaded successfully!")
+
+print(f"\n{'='*80}")
+print("🔍 PHASE 2: First Fine-tuning")
+print(f"{'='*80}")
+
+model = FastLanguageModel.get_peft_model(
+    model,
+    r=16,
+    target_modules=['k_proj', 'q_proj', 'v_proj', 'o_proj', "gate_proj", "down_proj", "up_proj"],
+    lora_alpha=16,
+    lora_dropout=0,
+    bias="none",
+    use_gradient_checkpointing="unsloth",
+    random_state=3407,
+    use_rslora=False,
+    loftq_config=None,
+)
+
+from unsloth import is_bfloat16_supported
+
+trainer = SFTTrainer(
+    model=model,
+    tokenizer=tokenizer,
+    train_dataset=dataset_train,
+    dataset_text_field="text",
+    max_seq_length=2048,
+    data_collator=DataCollatorForSeq2Seq(tokenizer=tokenizer),
+    dataset_num_proc=2,
+    packing=False,
+    args=TrainingArguments(
+        per_device_train_batch_size=2,
+        gradient_accumulation_steps=4,
+        warmup_ratio=0.1,
+        max_steps=10,  # Very short training for test
+        learning_rate=2e-4,
+        fp16=not is_bfloat16_supported(),
+        bf16=is_bfloat16_supported(),
+        logging_steps=5,
+        optim="adamw_8bit",
+        lr_scheduler_type="linear",
+        seed=3407,
+        output_dir="outputs",
+        report_to="none",
+    ),
+)
+
+trainer_stats = trainer.train()
+print("✅ First fine-tuning completed!")
+
+print(f"\n{'='*80}")
+print("🔍 PHASE 3: Save with Forced 4bit Merge")
+print(f"{'='*80}")
+
+model.save_pretrained_merged(
+    save_directory='./test_4bit_model',
+    tokenizer=tokenizer,
+    save_method="forced_merged_4bit"
+)
+
+print("✅ Model saved with forced 4bit merge!")
+
+print(f"\n{'='*80}")
+print("🔍 PHASE 4: Loading 4bit Model and Second Fine-tuning")
+print(f"{'='*80}")
+
+# Clean up first model
+del model
+del tokenizer
+torch.cuda.empty_cache()
+
+# Load the 4bit merged model
+model_4bit, tokenizer_4bit = FastLanguageModel.from_pretrained(
+    model_name="./test_4bit_model",
+    max_seq_length=2048,
+    load_in_4bit=True,
+    load_in_8bit=False,
+)
+
+tokenizer_4bit = get_chat_template(
+    tokenizer_4bit,
+    chat_template="llama-3.1",
+)
+
+print("✅ 4bit model loaded successfully!")
+
+# Add LoRA adapters to the 4bit model
+model_4bit = FastLanguageModel.get_peft_model(
+    model_4bit,
+    r=16,
+    target_modules=['k_proj', 'q_proj', 'v_proj', 'o_proj', "gate_proj", "down_proj", "up_proj"],
+    lora_alpha=16,
+    lora_dropout=0,
+    bias="none",
+    use_gradient_checkpointing="unsloth",
+    random_state=3407,
+    use_rslora=False,
+    loftq_config=None,
+)
+
+# Second fine-tuning
+trainer_4bit = SFTTrainer(
+    model=model_4bit,
+    tokenizer=tokenizer_4bit,
+    train_dataset=dataset_train,
+    dataset_text_field="text",
+    max_seq_length=2048,
+    data_collator=DataCollatorForSeq2Seq(tokenizer=tokenizer_4bit),
+    dataset_num_proc=2,
+    packing=False,
+    args=TrainingArguments(
+        per_device_train_batch_size=2,
+        gradient_accumulation_steps=4,
+        warmup_ratio=0.1,
+        max_steps=10,  # Very short training for test
+        learning_rate=2e-4,
+        fp16=not is_bfloat16_supported(),
+        bf16=is_bfloat16_supported(),
+        logging_steps=5,
+        optim="adamw_8bit",
+        lr_scheduler_type="linear",
+        seed=3407,
+        output_dir="outputs_4bit",
+        report_to="none",
+    ),
+)
+
+trainer_4bit.train()
+print("✅ Second fine-tuning on 4bit model completed!")
+
+print(f"\n{'='*80}")
+print("🔍 PHASE 5: Testing TypeError on Regular Merge (Should Fail)")
+print(f"{'='*80}")
+
+try:
+    model_4bit.save_pretrained_merged(
+        save_directory='./test_should_fail',
+        tokenizer=tokenizer_4bit
+        # No save_method specified, should default to regular merge
+    )
+    assert False, "Expected TypeError but merge succeeded!"
+except TypeError as e:
+    expected_error = "Base model should be a 16bits or mxfp4 base model for a 16bit model merge. Use `save_method=forced_merged_4bit` instead"
+    assert expected_error in str(e), f"Unexpected error message: {str(e)}"
+    print("✅ Correct TypeError raised for 4bit base model regular merge attempt!")
+    print(f"Error message: {str(e)}")
+
+print(f"\n{'='*80}")
+print("🔍 PHASE 6: Successful Save with Forced 4bit Method")
+print(f"{'='*80}")
+
+try:
+    model_4bit.save_pretrained_merged(
+        save_directory='./test_4bit_second',
+        tokenizer=tokenizer_4bit,
+        save_method="forced_merged_4bit"
+    )
+    print("✅ Successfully saved 4bit model with forced 4bit method!")
+except Exception as e:
+    assert False, f"Phase 6 failed unexpectedly: {e}"
+
+print(f"\n{'='*80}")
+print("🔍 CLEANUP")
+print(f"{'='*80}")
+
+# Cleanup
+safe_remove_directory("./outputs")
+safe_remove_directory("./outputs_4bit")
+safe_remove_directory("./unsloth_compiled_cache")
+safe_remove_directory("./test_4bit_model")
+safe_remove_directory("./test_4bit_second")
+safe_remove_directory("./test_should_fail")
+
+print("✅ All tests passed successfully!")