diff --git a/default.nix b/default.nix
index baee912b..1edc3fb0 100644
--- a/default.nix
+++ b/default.nix
@@ -88,13 +88,13 @@ let
     # FSBL startup
     fsbl-sd = pkgs.runCommand "zc706-${variant}-fsbl-sd"
       {
-        buildInputs = [ mkbootimage ];
+        buildInputs = [ mkbootimage zc706-fsbl];
       }
       ''
       # TODO: use self-built fsbl
       bifdir=`mktemp -d`
       cd $bifdir
-      ln -s ${./fsbl.elf} fsbl.elf
+      ln -s ${zc706-fsbl}/fsbl.elf fsbl.elf
       ln -s ${gateware}/top.bit top.bit
       ln -s ${firmware}/runtime.elf runtime.elf
       cat > boot.bif << EOF
diff --git a/fsbl.elf b/fsbl.elf
deleted file mode 100644
index e57257d6..00000000
Binary files a/fsbl.elf and /dev/null differ
diff --git a/fsbl.nix b/fsbl.nix
index 06397aff..2acd272d 100644
--- a/fsbl.nix
+++ b/fsbl.nix
@@ -10,6 +10,7 @@ pkgs.stdenv.mkDerivation {
     rev = "65c849ed46c88c67457e1fc742744f96db968ff1";
     sha256 = "1rvl06ha40dzd6s9aa4sylmksh4xb9dqaxq462lffv1fdk342pda";
   };
+  patches = [ ./fsbl.patch ];
   nativeBuildInputs = [
     pkgs.gnumake
     gnutoolchain.binutils
@@ -17,13 +18,14 @@ pkgs.stdenv.mkDerivation {
   ];
   patchPhase =
     ''
+    patch -p1 -i ${./fsbl.patch}
     patchShebangs lib/sw_apps/zynq_fsbl/misc/copy_bsp.sh
     echo 'SEARCH_DIR("${gnutoolchain.newlib}/arm-none-eabi/lib");' >> lib/sw_apps/zynq_fsbl/src/lscript.ld
     '';
   buildPhase =
     ''
     cd lib/sw_apps/zynq_fsbl/src
-    make BOARD=${board}
+    make BOARD=${board} "CFLAGS=-DFSBL_DEBUG_INFO -g"
     '';
   installPhase = 
     ''
diff --git a/fsbl.patch b/fsbl.patch
new file mode 100644
index 00000000..2537177c
--- /dev/null
+++ b/fsbl.patch
@@ -0,0 +1,31 @@
+diff --git a/lib/sw_apps/zynq_fsbl/src/Makefile b/lib/sw_apps/zynq_fsbl/src/Makefile
+index 0e3ccdf1c5..a5b02f386e 100644
+--- a/lib/sw_apps/zynq_fsbl/src/Makefile
++++ b/lib/sw_apps/zynq_fsbl/src/Makefile
+@@ -71,11 +71,14 @@ endif
+ all: $(EXEC)
+ 
+ $(EXEC): $(LIBS) $(OBJS) $(INCLUDES)
+-	cp $(BSP_DIR)/$(BOARD)/ps7_init.* .
+ 	$(LINKER) $(LD1FLAGS)  -o $@ $(OBJS) $(LDFLAGS)
+ 	rm -rf $(OBJS)
+-	
+-	
++
++.PHONY: ps7_init
++
++ps7_init:
++	cp $(BSP_DIR)/$(BOARD)/ps7_init.* .
++
+ $(LIBS): 
+ 	echo "Copying BSP files"
+ 	$(BSP_DIR)/copy_bsp.sh $(BOARD) $(CC)
+@@ -86,7 +89,7 @@ $(LIBS):
+         make -C $(BSP_DIR) -k all "CC=armcc" "AR=armar" "C_FLAGS= -O2 -c" "EC_FLAGS=--debug --wchar32"; \
+ 	fi;
+ 
+-%.o:%.c
++%.o:%.c ps7_init
+ 	$(CC) $(CC_FLAGS) $(CFLAGS) $(ECFLAGS) -c $< -o $@ $(INCLUDEPATH)
+ 
+ %.o:%.S