diff --git a/unsloth/device_type.py b/unsloth/device_type.py
index adc09b05df..68038de679 100644
--- a/unsloth/device_type.py
+++ b/unsloth/device_type.py
@@ -25,7 +25,6 @@
 import torch
 import functools
 from unsloth_zoo.utils import Version
-import inspect
 
 
 @functools.cache
@@ -78,21 +77,50 @@ def get_device_count():
 
 DEVICE_COUNT: int = get_device_count()
 
-# Check blocksize for 4bit -> 64 for CUDA, 128 for AMD
-# If AMD, we cannot load pre-quantized models for now :(
+# 4-bit quantization requires a block size of 64
+# this is not supported on AMD Instinct GPUs currently
+# | Device Type     | Warp Size | Block Size |
+# |-----------------|-----------|------------|
+# | CUDA            |    32     |     64     |
+# | Radeon (Navi)   |    32     |     64     |
+# | Instinct (MI)   |    64     |    128     |
+#
+# Since bitsandbytes 0.49.0, pre-quantized models with 64 blockwise now works
+# on Radeon GPUs, but not Instinct MI300x for eg [WIP]
+# See https://github.com/bitsandbytes-foundation/bitsandbytes/pull/1748
+
 ALLOW_PREQUANTIZED_MODELS: bool = True
 # HSA_STATUS_ERROR_EXCEPTION checks - sometimes AMD fails for BnB
 ALLOW_BITSANDBYTES: bool = True
 if DEVICE_TYPE == "hip":
     try:
-        from bitsandbytes.nn.modules import Params4bit
-
-        if "blocksize = 64 if not HIP_ENVIRONMENT else 128" in inspect.getsource(
-            Params4bit
-        ):
-            ALLOW_PREQUANTIZED_MODELS = False
         import bitsandbytes
-
-        ALLOW_BITSANDBYTES = Version(bitsandbytes.__version__) > Version("0.48.2.dev0")
     except:
-        pass
+        print(
+            "Unsloth: `bitsandbytes` is not installed - 4bit QLoRA unallowed, but 16bit and full finetuning works."
+        )
+        ALLOW_PREQUANTIZED_MODELS = False
+        ALLOW_BITSANDBYTES = False
+    if ALLOW_BITSANDBYTES:
+        ALLOW_BITSANDBYTES = Version(bitsandbytes.__version__) > Version("0.48.2.dev0")
+        if Version(bitsandbytes.__version__) > Version("0.49.0"):
+            try:
+                # Pre-quantized bitsandbytes models use blocksize 64, so we need to check the GPU
+                from bitsandbytes.cextension import ROCM_WARP_SIZE_64
+
+                ALLOW_PREQUANTIZED_MODELS = not ROCM_WARP_SIZE_64
+            except Exception as e:
+                print(
+                    "Unsloth: Checking `from bitsandbytes.cextension import ROCM_WARP_SIZE_64` had error = \n"
+                    f"{str(e)}\n"
+                    "4bit QLoRA disabled for now, but 16bit and full finetuning works."
+                )
+                ALLOW_PREQUANTIZED_MODELS = False
+                ALLOW_BITSANDBYTES = False
+        elif ALLOW_BITSANDBYTES:
+            from bitsandbytes.nn.modules import Params4bit
+
+            if "blocksize = 64 if not HIP_ENVIRONMENT else 128" in inspect.getsource(
+                Params4bit
+            ):
+                ALLOW_PREQUANTIZED_MODELS = False
diff --git a/unsloth/models/loader.py b/unsloth/models/loader.py
index 6148b1783e..a1e5756060 100644
--- a/unsloth/models/loader.py
+++ b/unsloth/models/loader.py
@@ -249,7 +249,7 @@ def from_pretrained(
                 model_name = new_model_name
 
         # Check if pre-quantized models are allowed
-        # For eg AMD GPUs need blocksize = 128, but our pre-quants are blocksize = 64
+        # For eg AMD Instinct GPUs need blocksize = 128, but our pre-quants are blocksize = 64
         if not ALLOW_PREQUANTIZED_MODELS and model_name.lower().endswith(
             ("-unsloth-bnb-4bit", "-bnb-4bit")
         ):
@@ -383,7 +383,7 @@ def from_pretrained(
             if not use_exact_model_name:
                 model_name = get_model_name(model_name, load_in_4bit)
             # Check if pre-quantized models are allowed
-            # For eg AMD GPUs need blocksize = 128, but our pre-quants are blocksize = 64
+            # For eg AMD Instinct GPUs need blocksize = 128, but our pre-quants are blocksize = 64
             if not ALLOW_PREQUANTIZED_MODELS and model_name.lower().endswith(
                 ("-unsloth-bnb-4bit", "-bnb-4bit")
             ):
@@ -790,7 +790,7 @@ def from_pretrained(
                 model_name = new_model_name
 
         # Check if pre-quantized models are allowed
-        # For eg AMD GPUs need blocksize = 128, but our pre-quants are blocksize = 64
+        # For eg AMD Instinct GPUs need blocksize = 128, but our pre-quants are blocksize = 64
         if not ALLOW_PREQUANTIZED_MODELS and model_name.lower().endswith(
             ("-unsloth-bnb-4bit", "-bnb-4bit")
         ):
@@ -1056,7 +1056,7 @@ def from_pretrained(
             if not use_exact_model_name:
                 model_name = get_model_name(model_name, load_in_4bit)
             # Check if pre-quantized models are allowed
-            # For eg AMD GPUs need blocksize = 128, but our pre-quants are blocksize = 64
+            # For eg AMD Instinct GPUs need blocksize = 128, but our pre-quants are blocksize = 64
             if not ALLOW_PREQUANTIZED_MODELS and model_name.lower().endswith(
                 ("-unsloth-bnb-4bit", "-bnb-4bit")
             ):