diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 9de56ac..631a653 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,7 +1,5 @@
 name: Docker
 on: [push]
-env:
-  KERNEL_VERSION: 6.5.9-ctsi-1
 jobs:
   build:
     runs-on: ubuntu-22.04
@@ -15,6 +13,9 @@ jobs:
       - name: Checkout Source Code
         uses: actions/checkout@v3
 
+      - name: Retrieve environment variables
+        run: make env >> $GITHUB_ENV
+
       - name: Download linux
         run: make download
 
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..294b3dc
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+linux-*.tar.gz
diff --git a/Makefile b/Makefile
index 6ffd371..a75c59f 100644
--- a/Makefile
+++ b/Makefile
@@ -20,7 +20,7 @@ TOOLCHAIN_SUFFIX ?=
 TOOLCHAIN_TAG ?= devel$(TOOLCHAIN_SUFFIX)
 TOOLCHAIN_CONFIG ?= configs/ct-ng-config$(TOOLCHAIN_SUFFIX)
 CONTAINER_BASE := /opt/cartesi/toolchain$(TOOLCHAIN_SUFFIX)
-KERNEL_VERSION ?= 6.5.9-ctsi-1
+KERNEL_VERSION ?= 6.5.13-ctsi-1-output-unification-test1
 KERNEL_SRCPATH := linux-$(KERNEL_VERSION).tar.gz
 
 BUILD_ARGS = --build-arg TOOLCHAIN_CONFIG=$(TOOLCHAIN_CONFIG) \
@@ -60,5 +60,8 @@ checksum: $(KERNEL_SRCPATH)
 
 download: checksum
 
-clean:
+env:
+	@echo KERNEL_VERSION="$(KERNEL_VERSION)"
+
+clean distclean:
 	rm -f $(KERNEL_SRCPATH)
diff --git a/configs/ct-ng-config b/configs/ct-ng-config
index d961054..a96c736 100644
--- a/configs/ct-ng-config
+++ b/configs/ct-ng-config
@@ -263,7 +263,7 @@ CT_LINUX_PKG_NAME="linux"
 # CT_LINUX_SRC_RELEASE is not set
 # CT_LINUX_SRC_DEVEL is not set
 CT_LINUX_SRC_CUSTOM=y
-CT_LINUX_CUSTOM_LOCATION="/tmp/build/linux-6.5.9-ctsi-1.tar.gz"
+CT_LINUX_CUSTOM_LOCATION="/tmp/build/linux-6.5.13-ctsi-1-output-unification-test1.tar.gz"
 CT_LINUX_PATCH_GLOBAL=y
 # CT_LINUX_PATCH_BUNDLED is not set
 # CT_LINUX_PATCH_LOCAL is not set
diff --git a/configs/ct-ng-config-rv64ima-lp64 b/configs/ct-ng-config-rv64ima-lp64
index c5e4fa1..c3712ab 100644
--- a/configs/ct-ng-config-rv64ima-lp64
+++ b/configs/ct-ng-config-rv64ima-lp64
@@ -263,7 +263,7 @@ CT_LINUX_PKG_NAME="linux"
 # CT_LINUX_SRC_RELEASE is not set
 # CT_LINUX_SRC_DEVEL is not set
 CT_LINUX_SRC_CUSTOM=y
-CT_LINUX_CUSTOM_LOCATION="/tmp/build/linux-6.5.9-ctsi-1.tar.gz"
+CT_LINUX_CUSTOM_LOCATION="/tmp/build/linux-6.5.13-ctsi-1-output-unification-test1.tar.gz"
 CT_LINUX_PATCH_GLOBAL=y
 # CT_LINUX_PATCH_BUNDLED is not set
 # CT_LINUX_PATCH_LOCAL is not set
diff --git a/shasumfile b/shasumfile
index 410f06a..becec34 100644
--- a/shasumfile
+++ b/shasumfile
@@ -1 +1 @@
-bfc4d196b90592a2a6bef83ead9e196da6ab6d5978b48ee5e8ccf02913355bc2  linux-6.5.9-ctsi-1.tar.gz
+db2be853d3986f8fa84d0d4a3cc8f3433b0b7772f4459a6efd439698e4b8dcde  linux-6.5.13-ctsi-1-output-unification-test1.tar.gz