diff --git a/cassava-bytestring.patch b/cassava-bytestring.patch
new file mode 100644
index 0000000..8645d29
--- /dev/null
+++ b/cassava-bytestring.patch
@@ -0,0 +1,12 @@
+--- cassava-0.5.1.0/cassava.cabal	2019-08-06 02:57:54.003159478 +0800
+@@ -53,6 +53,8 @@
+ 
+ flag bytestring--LT-0_10_4
+   description: [bytestring](https://hackage.haskell.org/haskell/package/bytestring) < 0.10.4
++  default: False
++  manual: True
+ 
+ Library
+   default-language: Haskell2010
+
+Diff finished.  Tue Aug  6 02:57:59 2019
diff --git a/ghc-cassava.spec b/ghc-cassava.spec
index 2b1c056..9e6e931 100644
--- a/ghc-cassava.spec
+++ b/ghc-cassava.spec
@@ -17,6 +17,7 @@ Url:            https://hackage.haskell.org/package/%{pkg_name}
 Source0:        https://hackage.haskell.org/package/%{pkgver}/%{pkgver}.tar.gz
 Source1:        https://hackage.haskell.org/package/%{pkgver}/%{pkg_name}.cabal#/%{pkgver}.cabal
 # End cabal-rpm sources
+Patch1:         cassava-bytestring.patch
 
 # Begin cabal-rpm deps:
 BuildRequires:  ghc-Cabal-devel
@@ -100,11 +101,11 @@ This package provides the Haskell %{pkg_name} profiling library.
 %setup -q -n %{pkgver}
 cp -bp %{SOURCE1} %{pkg_name}.cabal
 # End cabal-rpm setup
+%patch1 -p1 -b .orig1
 cabal-tweak-drop-dep bytestring-builder
 
 
 %build
-%define cabal_configure_options -f -bytestring--LT-0_10_4
 # Begin cabal-rpm build:
 %ghc_lib_build
 # End cabal-rpm build