diff --git a/.gitmodules b/.gitmodules
index d434c3db8..ba8877ce5 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -17,9 +17,6 @@
 [submodule "addins/embench-iot"]
 	path = addins/embench-iot
 	url = https://github.com/embench/embench-iot
-[submodule "addins/book_flow"]
-	path = addins/book_flow
-	url = https://github.com/stineje/book_flow
 [submodule "addins/sky130_osu_sc_t18"]
 	path = addins/sky130_osu_sc_t18
 	url = https://foss-eda-tools.googlesource.com/skywater-pdk/libs/sky130_osu_sc_t18
diff --git a/addins/book_flow b/addins/book_flow
deleted file mode 160000
index 5ef17d725..000000000
--- a/addins/book_flow
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 5ef17d725e472ef414e5581bf25805236e6a60ca