diff --git a/.github/workflows/validate-book-build.yml b/.github/workflows/validate-book-build.yml
index 7eb4859..35aafa5 100644
--- a/.github/workflows/validate-book-build.yml
+++ b/.github/workflows/validate-book-build.yml
@@ -29,4 +29,4 @@ jobs:
           options: -v ${{ github.workspace }}:/app
           run: |
             cd /app/book
-            make -j build_pdf build_serif_ebook
+            make -j build_pdf build_ebook
diff --git a/makefile b/makefile
index 1e9b597..a52e6e3 100644
--- a/makefile
+++ b/makefile
@@ -22,7 +22,7 @@ website: mrproper
 
 .PHONY: validate
 validate: mrproper
-	docker run -it -v $(PWD):/opt/repo $(DOCKER_IMAGE) /bin/bash -c "cd /opt/repo/book && make -j build_pdf build_serif_ebook"
+	docker run -it -v $(PWD):/opt/repo $(DOCKER_IMAGE) /bin/bash -c "cd /opt/repo/book && make -j build_pdf build_ebook"
 
 .PHONY: mrproper
 mrproper: