diff --git a/.gitignore b/.gitignore
index 00dd0c105..d1c065e87 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,16 @@
 /toolchain-*
 /sdk-*
 /.gitignore
+result
+##### TUP GITIGNORE #####
+##### Lines below automatically generated by Tup.
+##### Do not edit.
+.tup
+/.gitignore
+/Makefile
+/bin-list
+/depot
+/pkg.sed
+/public
+/raw-list
+/versions.sed
diff --git a/Tuprules.tup b/Tuprules.tup
index e7ed3776d..ee0ffc1b3 100644
--- a/Tuprules.tup
+++ b/Tuprules.tup
@@ -1,5 +1,17 @@
 .gitignore
 
+ifeq (@(TUP_ARCH),i386)
+CC_MARCH = -march=i686 -m32
+LD_MARCH = -melf_i386
+endif
+
+ifeq (@(TUP_ARCH),x86_64)
+CC_MARCH = -m64 -mcmodel=large
+LD_MARCH = -melf_x86_64
+endif
+
+GENODE_DIR = $(TUP_CWD)/upstream
+
 ifeq ($(RAW_NAME),)
 RAW_NAME = $(TARGET_NAME)
 endif
@@ -22,7 +34,7 @@ endif
 
 DEPOT_DIR  = $(TUP_CWD)/depot
 DEPOT_RAW_DIR = $(DEPOT_DIR)/raw
-DEPOT_BIN_DIR = $(DEPOT_DIR)/bin/@(TUP_ARCH)
+DEPOT_BIN_DIR = $(DEPOT_DIR)/bin
 DEPOT_PKG_DIR = $(DEPOT_DIR)/pkg
 
 PUBLIC_DIR = $(TUP_CWD)/public
@@ -99,17 +111,19 @@ SDK_INCLUDE = $(TUP_CWD)/sdk.tup
 
 ERRATA_DIR = $(TUP_CWD)/errata
 
-PKG_CONFIG = PKG_CONFIG_PATH=@(PKG_CONFIG_PATH) pkg-config
+export PKG_CONFIG_PATH
+PKG_CONFIG = PKG_CONFIG_PATH=$(GENODE_DIR)/pkg-config:$PKG_CONFIG_PATH pkg-config
 
 ifndef TOOL_CHAIN_PREFIX
 	error TOOL_CHAIN_PREFIX not configured
 endif
 
-CC = $(TOOL_CHAIN_PREFIX)gcc
-CXX = $(TOOL_CHAIN_PREFIX)g++
-LD= $(TOOL_CHAIN_PREFIX)ld
-AR = $(TOOL_CHAIN_PREFIX)ar
+CC = @(TOOL_CHAIN_PREFIX)gcc
+CXX = @(TOOL_CHAIN_PREFIX)g++
+LD= @(TOOL_CHAIN_PREFIX)ld
+AR = @(TOOL_CHAIN_PREFIX)ar
+OBJCOPY = @(TOOL_CHAIN_PREFIX)objcopy
 
 !cc = |> ^ CC %f^ $(CC) $(DEFINES) $(CFLAGS) $(CFLAGS_%e) $(CFLAGS_%f) -c %f -o %o |>
-!cxx = |> ^ CC %f^ $(CC) $(DEFINES) $(CXXFLAGS) $(CXXFLAGS_%e) $(CXXFLAGS_%f) -c %f -o %o |>
+!cxx = | $(GENODE_DIR)/<pkg-config> |> ^ CC %f^ $(CC) $(DEFINES) $(CXXFLAGS) $(CXXFLAGS_%e) $(CXXFLAGS_%f) -c %f -o %o |>
 !ld = |> ^ LD %o^ $(LD) $(LDFLAGS) %f -o %o |>
diff --git a/default.nix b/default.nix
index 1fc80ec9a..594d55c38 100644
--- a/default.nix
+++ b/default.nix
@@ -1,9 +1,15 @@
 { pkgs ? import <nixpkgs> {} }: with pkgs;
 
+let
+  lddir = ./upstream/repos/base/src/ld;
+  toolchain = import ./errata/toolchain.nix { inherit pkgs; };
+  sdk = import ./sdk { inherit pkgs toolchain; };
+  ports = import ./upstream/repos/libports/ports { };
+in
 pkgs.mkShell {
   name = "genode-dev-env";
   nativeBuildInputs =
-    [ (import ./errata/toolchain.nix { inherit pkgs; })
+    [ toolchain
       stdenv.glibc.dev
       git tup
       ccache
@@ -13,6 +19,7 @@ pkgs.mkShell {
       findutils
       autoconf264
       autogen
+      cdrtools
 
       expect libxml2 syslinux qemu xorriso
 
@@ -38,8 +45,15 @@ pkgs.mkShell {
       ncurses
     ];
 
+  passthru = { inherit lddir sdk toolchain; };
+
   shellHook =
     ''
+      export SDK_DIR=${sdk}
+      export LD_DIR=${lddir}
+      export PKG_CONFIG_PATH=${sdk}/pkg-config
+      export TOOLCHAIN_DIR=${toolchain}
+      export SYSLINUX=${syslinux}
       export PROMPT_DIRTRIM=2
       export PS1="\[\033[1;30m\]Genode-dev [\[\033[1;37m\]\w\[\033[1;30m\]] $\[\033[0m\] "
       export PS2="\[\033[1;30m\]>\[\033[0m\] "
diff --git a/tests/iso/Tupfile b/tests/iso/Tupfile
index 66b0c6b95..8e32789f5 100644
--- a/tests/iso/Tupfile
+++ b/tests/iso/Tupfile
@@ -1,31 +1,30 @@
 include_rules
 export SYSLINUX
 
+: config |> \
+	echo %f | awk -f a.awk >> %o; \
+	echo %f | awk -f b.awk >> %o; \
+	echo %f | awk -f c.awk >> %o; \
+|> modules.s
 
-# boot_modules.o {modules}
+: modules.s |> $(CC) $(CC_MARCH) -c %f -o %o |> boot_modules.o
 
 LINK_ADDRESS = 0x01000000
 
-# : {modules}
-
-: modules.txt |> \
-	awk -f a.awk < %f >> %o; \
-	awk -f b.awk < %f >> %o; \
-	awk -f c.awk < %f >> %o; \
-|> modules.s
-
-: | \
+: boot_modules.o | \
 	$(GENODE_DIR)/repos/base-nova/<core> \
-	$(GENODE_DIR)/repos/base-nova/<ld> \
 |> \
-		$(CXX) -nostdlib \
+		$(CXX) $(CC_MARCH) -nostdlib \
+		-Wl,-T -Wl,$(GENODE_DIR)/repos/base/src/ld/genode.ld \
 		-Wl,-z -Wl,max-page-size=0x1000 \
 		-Wl,-Ttext=$(LINK_ADDRESS) -Wl,-gc-sections \
 		-Wl,-nostdlib \
 		-Wl,--whole-archive -Wl,--start-group \
-		%<core> %<ld> \
+		%<core> %f \
 		-Wl,--no-whole-archive \
-		-Wl,--end-group $libgcc -o %o \
+		-Wl,--end-group \
+		`$(CXX) $(CC_MARCH) -print-libgcc-file-name` \
+		-o %o \
 |> image.elf
 
 : image.elf |> gzip --keep %f |> %b.gz
diff --git a/upstream b/upstream
index 11d2a2957..49098b9af 160000
--- a/upstream
+++ b/upstream
@@ -1 +1 @@
-Subproject commit 11d2a2957af3794ba9776d0958c2165699a77ffd
+Subproject commit 49098b9af3d089ca4a367d8e12c95d7b792460df