diff --git a/GPTQ-for-LLaMa/gradient_checkpointing.py b/GPTQ-for-LLaMa/gradient_checkpointing.py
new file mode 100644
index 0000000..b75fd2c
--- /dev/null
+++ b/GPTQ-for-LLaMa/gradient_checkpointing.py
@@ -0,0 +1,61 @@
+from transformers.models.llama.modeling_llama import LlamaDecoderLayer
+from torch.utils.checkpoint import checkpoint
+from torch.autograd import Variable
+import torch
+from torch import nn
+import numpy as np
+
+
+class NewForward:
+
+    def __init__(self, layer):
+        self.layer = layer
+        self.apply_patch()
+
+    def apply_patch(self):
+        self.layer.old_forward_for_cp = self.layer.forward
+        self.layer.forward = self.new_forward
+
+    def new_forward(self, *args, **kwargs):
+        def func(*args):
+            return self.layer.old_forward_for_cp(*args, **kwargs)
+        output = checkpoint(func, *args)
+        return output
+
+
+class VarWrapper:
+
+    def __init__(self, model):
+        self.model = model
+        self.apply_patch()
+        print('Var Wrapper Patch Applied')
+
+    def apply_patch(self):
+        self.model.old_forward_for_cp = self.model.forward
+        self.model.forward = self.new_forward
+
+    def new_forward(self, *args, **kwargs):
+        out = self.model.old_forward_for_cp(*args, **kwargs)
+        out = Variable(out.data, requires_grad=True)
+        return out
+
+
+def apply_gradient_checkpointing(model, checkpoint_ratio=1):
+    new_forwards = []
+    modules = []
+    for n, m in model.named_modules():
+        if isinstance(m, LlamaDecoderLayer):
+            modules.append(m)
+    if checkpoint_ratio < 1 and checkpoint_ratio > 0:
+        checkpoint_locs = np.array((np.linspace(0, 1, int(len(modules) * checkpoint_ratio)) * (len(modules)-1)).round(), dtype=int)
+    else:
+        checkpoint_locs = np.arange(len(modules))
+    for i in checkpoint_locs:
+        m = modules[i]
+        new_forwards.append(NewForward(m))
+        print('Forward Patch Applied For Block {}'.format(i))
+    for n, m in model.named_modules():
+        if isinstance(m, torch.nn.Embedding):
+            wrapper = VarWrapper(m)
+            break
+    return new_forwards, wrapper
diff --git a/GPTQ-for-LLaMa/quant_cuda_kernel.cu b/GPTQ-for-LLaMa/quant_cuda_kernel.cu
index 0077650..ed9627a 100644
--- a/GPTQ-for-LLaMa/quant_cuda_kernel.cu
+++ b/GPTQ-for-LLaMa/quant_cuda_kernel.cu
@@ -4,8 +4,10 @@
 #include <cuda_runtime.h>
 #include <cuda_fp16.h>
 
+#ifdef __CUDA_ARCH__
+#if __CUDA_ARCH__ < 700 && __CUDA_ARCH__ > 600
 // adapted from https://github.com/torch/cutorch/blob/master/lib/THC/THCAtomics.cuh
-__device__ __forceinline__ void atomicAdd(c10::Half* address, c10::Half val) {
+__device__ __forceinline__ void atomicAddHalf(__half* address, c10::Half val) {
     unsigned int *address_as_ui = reinterpret_cast<unsigned int *>(reinterpret_cast<char *>(address) - (reinterpret_cast<size_t>(address) & 2));
     unsigned int old = *address_as_ui;
     unsigned int assumed;
@@ -22,6 +24,8 @@ __device__ __forceinline__ void atomicAdd(c10::Half* address, c10::Half val) {
     // Note: uses integer comparison to avoid hang in case of NaN (since NaN != NaN)
     } while (assumed != old);
 }
+#endif
+#endif
 
 template <typename scalar_t>
 __global__ void VecQuant2MatMulKernel(
@@ -543,7 +547,14 @@ __global__ void VecQuant4MatMulHalfKernel(
   }
   
   __half* mul2 = (__half*)mul;
+#ifdef __CUDA_ARCH__
+#if __CUDA_ARCH__ < 700 && __CUDA_ARCH__ > 600
+  atomicAddHalf(&mul2[b * width + w], res);
+#else
   atomicAdd(&mul2[b * width + w], res);
+#endif
+#endif
+
 }
 
 void vecquant4matmul_half_cuda(
@@ -616,7 +627,13 @@ __global__ void VecQuant4TransposeMatMulHalfKernel(
   }
   
   __half* mul2 = (__half*)mul;
+#ifdef __CUDA_ARCH__
+#if __CUDA_ARCH__ < 700 && __CUDA_ARCH__ > 600
+  atomicAddHalf(&mul2[n_cols * height * 8 + n_rows], res);
+#else
   atomicAdd(&mul2[n_cols * height * 8 + n_rows], res);
+#endif
+#endif
 }
 
 void vecquant4transposematmul_half_cuda(
diff --git a/README.md b/README.md
index c926eac..7f64534 100644
--- a/README.md
+++ b/README.md
@@ -1,11 +1,22 @@
 # Alpaca Lora 4bit
 Made some adjust for the code in peft and gptq for llama, and make it possible for lora finetuning with a 4 bits base model. The same adjustment can be made for 2, 3 and 8 bits.
 <br>
-~Still numerically unstable.~ Resolved.
+* Install Manual by s4rduk4r: https://github.com/s4rduk4r/alpaca_lora_4bit_readme/blob/main/README.md
+
+# Update Logs
+* Resolved numerically unstable issue
 <br>
-Reconstruct fp16 matrix from 4bit data and call torch.matmul largely increased the inference speed.
+
+* Reconstruct fp16 matrix from 4bit data and call torch.matmul largely increased the inference speed.
 <br>
-Added install script for windows and linux.
+
+* Added install script for windows and linux.
+<br>
+
+* Added Gradient Checkpointing. Now It can finetune 30b model 4bit on a single GPU with 24G VRAM with Gradient Checkpointing enabled. (finetune.py updated) (but would reduce training speed, so if having enough VRAM this option is not needed)
+<br>
+
+* Added install manual by s4rduk4r
 <br>
 
 # Requirements
diff --git a/finetune.py b/finetune.py
index 41dc376..6224f2e 100644
--- a/finetune.py
+++ b/finetune.py
@@ -127,10 +127,10 @@ if not ft_config.skip:
 
     print('Train completed.')
 
-if not ft_config.checkpoint:
-    # Save Model
-    model.save_pretrained(ft_config.lora_out_dir)
-else:
-    raise NotImplemented("TODO: Merge model + LoRA and save the whole checkpoint")
+# Save Model
+model.save_pretrained(ft_config.lora_out_dir)
 
-print('Model Saved.')
+if ft_config.checkpoint:
+    print("Warning: Merge model + LoRA and save the whole checkpoint not implemented yet.")
+    
+print('Model Saved.')
\ No newline at end of file
diff --git a/install.bat b/install.bat
index bf5e817..bd79a55 100644
--- a/install.bat
+++ b/install.bat
@@ -15,8 +15,9 @@ REM replace ./repository/GPTQ-for-LLaMa/quant_cuda.cpp and quant_cuda_kernel.cu
 copy .\GPTQ-for-LLaMa\quant_cuda.cpp .\repository\GPTQ-for-LLaMa\quant_cuda.cpp /Y
 copy .\GPTQ-for-LLaMa\quant_cuda_kernel.cu .\repository\GPTQ-for-LLaMa\quant_cuda_kernel.cu /Y
 
-REM copy autograd_4bit.py into ./repository/GPTQ-for-LLaMa/autograd_4bit.py
+REM copy files into ./repository/GPTQ-for-LLaMa/
 copy .\GPTQ-for-LLaMa\autograd_4bit.py .\repository\GPTQ-for-LLaMa\autograd_4bit.py /Y
+copy .\GPTQ-for-LLaMa\gradient_checkpointing.py .\repository\GPTQ-for-LLaMa\gradient_checkpointing.py /Y
 
 REM install quant_cuda
 cd .\repository\GPTQ-for-LLaMa
diff --git a/install.sh b/install.sh
index be4c802..fd5a67c 100644
--- a/install.sh
+++ b/install.sh
@@ -19,8 +19,9 @@ cp ./peft/tuners/lora.py ./repository/peft/src/peft/tuners/lora.py
 cp ./GPTQ-for-LLaMa/quant_cuda.cpp ./repository/GPTQ-for-LLaMa/quant_cuda.cpp
 cp ./GPTQ-for-LLaMa/quant_cuda_kernel.cu ./repository/GPTQ-for-LLaMa/quant_cuda_kernel.cu
 
-# Copy autograd_4bit.py into ./repository/GPTQ-for-LLaMa/autograd_4bit.py
+# Copy files into ./repository/GPTQ-for-LLaMa/
 cp ./GPTQ-for-LLaMa/autograd_4bit.py ./repository/GPTQ-for-LLaMa/autograd_4bit.py
+cp ./GPTQ-for-LLaMa/gradient_checkpointing.py ./repository/GPTQ-for-LLaMa/gradient_checkpointing.py
 
 # Install quant_cuda and cd into ./repository/GPTQ-for-LLaMa
 cd ./repository/GPTQ-for-LLaMa