diff --git a/README.adoc b/README.adoc
index 7fbc047..0e00d67 100644
--- a/README.adoc
+++ b/README.adoc
@@ -7316,7 +7316,7 @@ TODO: `arm` broken on kernel 4.18 with:
 Internal error: Oops - undefined instruction
 ....
 
-Workaround by checking out kernel 4.17 as explained at <<linux-kernel-build-variants>>.
+Workaround by checking out kernel 4.17 as explained at <<linux-kernel-build-variants>>. Bisected down to kernel 1d4238c56f9816ce0f9c8dbe42d7f2ad81cb6613, gem5 is not implementing the `CSDB` instruction.
 
 === gem5 vs QEMU