diff --git a/Makefile b/Makefile
index 7d6e4afc7f..f6ab07e408 100644
--- a/Makefile
+++ b/Makefile
@@ -279,6 +279,7 @@ STAMP_DIR:=$(BASE_DIR)/stamps
 BINARIES_DIR:=$(BASE_DIR)/images
 TARGET_DIR:=$(BASE_DIR)/target
 TOOLCHAIN_DIR=$(BASE_DIR)/toolchain
+TOOLCHAIN_EXTERNAL_DIR=$(BASE_DIR)/external-toolchain
 TARGET_SKELETON=$(TOPDIR)/fs/skeleton
 
 BR2_DEPENDS_DIR=$(BUILD_DIR)/buildroot-config
@@ -600,7 +601,7 @@ endif
 
 clean:
 	rm -rf $(STAGING_DIR) $(TARGET_DIR) $(BINARIES_DIR) $(HOST_DIR) \
-		$(STAMP_DIR) $(BUILD_DIR) $(TOOLCHAIN_DIR)
+		$(STAMP_DIR) $(BUILD_DIR) $(TOOLCHAIN_DIR) $(TOOLCHAIN_EXTERNAL_DIR)
 
 distclean: clean
 ifeq ($(DL_DIR),$(TOPDIR)/dl)
diff --git a/package/Makefile.in b/package/Makefile.in
index d448a7edf6..36bd59f372 100644
--- a/package/Makefile.in
+++ b/package/Makefile.in
@@ -114,13 +114,13 @@ REAL_GNU_TARGET_NAME=$(ARCH)-unknown-linux-$(LIBC)$(ABI)
 ifeq ($(BR2_TOOLCHAIN_BUILDROOT),y)
 TARGET_CROSS=$(STAGING_DIR)/usr/bin/$(REAL_GNU_TARGET_NAME)-
 else ifeq ($(BR2_TOOLCHAIN_EXTERNAL),y)
-TOOLCHAIN_EXTERNAL_PREFIX:=$(call qstrip,$(BR2_TOOLCHAIN_EXTERNAL_PREFIX))
-TOOLCHAIN_EXTERNAL_PATH:=$(call qstrip,$(BR2_TOOLCHAIN_EXTERNAL_PATH))
-ifneq ($(TOOLCHAIN_EXTERNAL_PATH),)
-TARGET_CROSS=$(TOOLCHAIN_EXTERNAL_PATH)/bin/$(TOOLCHAIN_EXTERNAL_PREFIX)-
+TOOLCHAIN_EXTERNAL_PREFIX=$(call qstrip,$(BR2_TOOLCHAIN_EXTERNAL_PREFIX))
+ifeq ($(BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD),y)
+TOOLCHAIN_EXTERNAL_LOCATION=$(TOOLCHAIN_EXTERNAL_DIR)
 else
-TARGET_CROSS=$(TOOLCHAIN_EXTERNAL_PREFIX)-
+TOOLCHAIN_EXTERNAL_LOCATION=$(call qstrip,$(BR2_TOOLCHAIN_EXTERNAL_PATH))
 endif
+TARGET_CROSS=$(TOOLCHAIN_EXTERNAL_LOCATION)/bin/$(TOOLCHAIN_EXTERNAL_PREFIX)-
 else ifeq ($(BR2_TOOLCHAIN_CTNG),y)
 TARGET_CROSS=$(TOOLCHAIN_DIR)/bin/$(REAL_GNU_TARGET_NAME)-
 endif
diff --git a/toolchain/Config.in b/toolchain/Config.in
index d476cbf504..8baa0c14ca 100644
--- a/toolchain/Config.in
+++ b/toolchain/Config.in
@@ -13,6 +13,10 @@ config BR2_TOOLCHAIN_BUILDROOT
 
 config BR2_TOOLCHAIN_EXTERNAL
 	bool "External toolchain"
+	help
+	  Select if you want to use an existing cross-compiling
+	  toolchain. Buildroot can either download automatically a
+	  toolchain, or use an already installed toolchain.
 
 config BR2_TOOLCHAIN_CTNG
 	bool "Crosstool-NG toolchain"
@@ -29,6 +33,5 @@ source "toolchain/toolchain-external/Config.in"
 source "toolchain/toolchain-crosstool-ng/Config.in"
 source "toolchain/toolchain-common.in"
 source "toolchain/toolchain-buildroot/Config.in.2"
-source "toolchain/toolchain-external/Config.in.2"
 
 endmenu
diff --git a/toolchain/toolchain-external/Config.in b/toolchain/toolchain-external/Config.in
index f0268a739a..c2602d2369 100644
--- a/toolchain/toolchain-external/Config.in
+++ b/toolchain/toolchain-external/Config.in
@@ -1,15 +1,142 @@
-#
-
 if BR2_TOOLCHAIN_EXTERNAL
-choice
-	prompt "External toolchain C library"
-	default BR2_TOOLCHAIN_EXTERNAL_UCLIBC
 
-config BR2_TOOLCHAIN_EXTERNAL_UCLIBC
-	bool "uClibc"
+choice
+	prompt "Toolchain"
+
+config BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM201009
+	bool "CodeSourcery ARM 2010.09"
+	depends on BR2_arm
+	select BR2_TOOLCHAIN_EXTERNAL_GLIBC
+	help
+	  Toolchain for the ARM architecture, from CodeSourcery. It
+	  uses gcc 4.5.1, binutils 2.20, glibc 2.11 and gdb 7.2.50,
+	  kernel headers 2.6.35.2. It has support for the following
+	  variants:
+            - ARMv5TE, little endian, soft-float, glibc
+            - ARMv4T, little endian, soft-float, glibc
+            - ARMv7-A, Thumb 2, little endian, soft-float, glibc
+
+config BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM2010Q1
+	bool "CodeSourcery ARM 2010q1"
+	depends on BR2_arm
+	select BR2_TOOLCHAIN_EXTERNAL_GLIBC
+	help
+	  Toolchain for the ARM architecture, from CodeSourcery. It
+	  uses gcc 4.4.1, binutils 2.19, glibc 2.11, gdb 7.0.50 and
+	  kernel headers 2.6.32. It has support for the following
+	  variants:
+             - ARMv5T, little endian, soft-float, glibc
+             - ARMv4T, little endian, soft-float, glibc
+             - ARMv7-A, Thumb 2, little endian, soft-float, glibc
+
+config BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM2009Q1
+	bool "CodeSourcery ARM 2009q1"
+	depends on BR2_arm
+	select BR2_TOOLCHAIN_EXTERNAL_GLIBC
+	help
+	  Toolchain for the ARM architecture, from CodeSourcery. It
+	  uses gcc 4.3.3, binutils 2.19, glibc 2.8 and gdb 6.8 and
+	  kernel headers 2.6.30. It has support for the following
+	  variants:
+            - ARMv5T, little endian, soft-float, glibc
+            - ARMv4T, little endian, soft-float, glibc
+            - ARMv7-A, Thumb 2, little endian, soft-float, glibc
+
+config BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_MIPS44
+	bool "CodeSourcery MIPS 4.4"
+	depends on BR2_mips || BR2_mipsel
+	select BR2_TOOLCHAIN_EXTERNAL_GLIBC
+	help
+	  Toolchain for the MIPS architecture, from CodeSourcery. It
+	  uses gcc 4.4.1, binutils 2.19, glibc 2.11, uClibc 0.9.30 and
+	  gdb 7.0, kernel headers 2.6.32. It has support for the
+	  following variants:
+            - MIPS32 O32 big endian glibc
+            - MIPS32 O32 little endian glibc
+            - MIPS32 big endian soft float glibc
+            - MIPS32 little endian soft float glibc
+            - MIPS32 big endian microMIPS glibc
+            - MIPS32 little endian microMIPS glibc
+            - MIPS32 big endian soft float microMIPS glibc
+            - MIPS32 little endian soft float microMIPS glibc
+            - MIPS32 big endian uclibc
+            - MIPS32 little endian uclibc
+            - MIPS32 big endian soft float uclibc
+            - MIPS32 little endian soft float uclibc
+
+config BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_POWERPC201009
+	bool "CodeSoucery PowerPC 2010.09"
+	depends on BR2_powerpc
+	select BR2_TOOLCHAIN_EXTERNAL_GLIBC
+	help
+	  Toolchain for the PowerPC architecture, from
+	  CodeSourcery. It uses gcc 4.5.1, binutils 2.20, glibc 2.11,
+	  gdb 7.2.50 and kernel headers 2.6.35.2. It has support for
+	  the following variants:
+            - 603 glibc, 32 bits
+            - 603 soft float glibc, 32 bits
+            - e600 altivec glibc, 32 bits
+            - e500v1 glibc, 32 bits
+            - e500v2 glibc, 32 bits
+            - e500mc glibc, 32 bits
+            - 970 glibc hard-float, 64 bits
+
+config BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_SH201009
+	bool "CodeSoucery PowerPC 2010.09"
+	depends on BR2_sh
+	select BR2_TOOLCHAIN_EXTERNAL_GLIBC
+	help
+	  Toolchain for the SuperH architecture, from CodeSourcery. It
+	  uses gcc 4.5.1, binutils 2.20, glibc 2.11, uClibc 0.9.30,
+	  gdb 7.2.50 and kernel headers 2.6.35.2. It has support for
+	  the following variants:
+            - SH4A, glibc, little endian
+            - SH4A, glibc, big endian
+	    - SH4A, uClibc, little endian
+            - SH4A, uClibc, big endian
+
+config BR2_TOOLCHAIN_EXTERNAL_CUSTOM
+       bool "Custom toolchain"
+       help
+         Use this option to use a custom toolchain pre-installed on
+         your system.
+
+endchoice
+
+config BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD
+	bool "Download toolchain automatically"
+	default y
+	depends on !BR2_TOOLCHAIN_EXTERNAL_CUSTOM
+	help
+	  When enabled, Buildroot will automatically download and
+	  install the selected external toolchain. When disabled,
+	  Buildroot will use a pre-installed toolchain.
+
+config BR2_TOOLCHAIN_EXTERNAL_PATH
+	string "Toolchain path"
+	default "/path/to/toolchain/usr"
+	depends on !BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD
+	help
+	  Path to where the external toolchain is installed.
+
+config BR2_TOOLCHAIN_EXTERNAL_CUSTOM_PREFIX
+	string "Toolchain prefix"
+	depends on BR2_TOOLCHAIN_EXTERNAL_CUSTOM
+	default "$(ARCH)-linux"
+
+config BR2_TOOLCHAIN_EXTERNAL_PREFIX
+	string
+	default "arm-none-linux-gnueabi" if BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM2009Q1
+	default "arm-none-linux-gnueabi" if BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM2010Q1
+	default "arm-none-linux-gnueabi" if BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM201009
+	default "mips-linux-gnu"         if BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_MIPS44
+	default "powerpc-linux-gnu"      if BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_POWERPC201009
+	default "sh4-linux-gnu"          if BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_SH201009
+	default $(BR2_TOOLCHAIN_EXTERNAL_CUSTOM_PREFIX) \
+					 if BR2_TOOLCHAIN_EXTERNAL_CUSTOM
 
 config BR2_TOOLCHAIN_EXTERNAL_GLIBC
-	bool "glibc"
+	bool
 	select BR2_LARGEFILE
 	select BR2_INET_IPV6
 	select BR2_INET_RPC
@@ -17,9 +144,26 @@ config BR2_TOOLCHAIN_EXTERNAL_GLIBC
 	select BR2_ENABLE_LOCALE
 	select BR2_PROGRAM_INVOCATION
 
+config BR2_TOOLCHAIN_EXTERNAL_UCLIBC
+	bool
+
+if BR2_TOOLCHAIN_EXTERNAL_CUSTOM
+
+choice
+	prompt "External toolchain C library"
+	default BR2_TOOLCHAIN_EXTERNAL_CUSTOM_UCLIBC
+
+config BR2_TOOLCHAIN_EXTERNAL_CUSTOM_UCLIBC
+	bool "uClibc"
+	select BR2_TOOLCHAIN_EXTERNAL_UCLIBC
+
+config BR2_TOOLCHAIN_EXTERNAL_CUSTOM_GLIBC
+	bool "glibc"
+	select BR2_TOOLCHAIN_EXTERNAL_GLIBC
+
 endchoice
 
-if BR2_TOOLCHAIN_EXTERNAL_UCLIBC
+if BR2_TOOLCHAIN_EXTERNAL_CUSTOM_UCLIBC
 
 config BR2_TOOLCHAIN_EXTERNAL_LARGEFILE
 	bool "Toolchain has large file support?"
@@ -70,7 +214,9 @@ config BR2_TOOLCHAIN_EXTERNAL_PROGRAM_INVOCATION
 	  invocation support. If you don't know, leave the default
 	  value, Buildroot will tell you if it's correct or not.
 
-endif
+endif # BR2_TOOLCHAIN_EXTERNAL_CUSTOM_UCLIBC
+
+endif # BR2_TOOLCHAIN_EXTERNAL_CUSTOM
 
 config BR2_TOOLCHAIN_EXTERNAL_STRIP
 	bool
@@ -78,4 +224,6 @@ config BR2_TOOLCHAIN_EXTERNAL_STRIP
 	prompt "Strip shared libraries"
 	help
 	  Strip shared libraries copied from the external toolchain.
-endif
+
+endif # BR2_TOOLCHAIN_EXTERNAL
+
diff --git a/toolchain/toolchain-external/Config.in.2 b/toolchain/toolchain-external/Config.in.2
deleted file mode 100644
index 489558c0f6..0000000000
--- a/toolchain/toolchain-external/Config.in.2
+++ /dev/null
@@ -1,17 +0,0 @@
-#
-
-if BR2_TOOLCHAIN_EXTERNAL
-config BR2_TOOLCHAIN_EXTERNAL_PATH
-	string "External toolchain path"
-	default "/path/to/staging_dir/usr"
-	help
-	  Path to where the external toolchain is installed.
-
-config BR2_TOOLCHAIN_EXTERNAL_PREFIX
-	string "External toolchain prefix"
-	default "$(ARCH)-linux"
-	help
-	  This the the external toolchain prefix. For example:
-	    armeb-unknown-linux-gnu, mipsel-unknown-linux-gnu, etc.
-
-endif
diff --git a/toolchain/toolchain-external/ext-tool.mk b/toolchain/toolchain-external/ext-tool.mk
index 53ad636acf..7a1791473c 100644
--- a/toolchain/toolchain-external/ext-tool.mk
+++ b/toolchain/toolchain-external/ext-tool.mk
@@ -2,8 +2,9 @@
 #
 # This file implements the support for external toolchains, i.e
 # toolchains that have not been produced by Buildroot itself and that
-# are already available on the system on which Buildroot runs. So far,
-# we have tested this with:
+# Buildroot can download from the Web or that are already available on
+# the system on which Buildroot runs. So far, we have tested this
+# with:
 #
 #  * Toolchains generated by Crosstool-NG
 #  * Toolchains generated by Buildroot
@@ -13,17 +14,21 @@
 #
 # The basic principle is the following
 #
-#  1. Perform some checks on the conformity between the toolchain
-#  configuration described in the Buildroot menuconfig system, and the
-#  real configuration of the external toolchain. This is for example
-#  important to make sure that the Buildroot configuration system
-#  knows whether the toolchain supports RPC, IPv6, locales, large
-#  files, etc. Unfortunately, these things cannot be detected
-#  automatically, since the value of these options (such as
-#  BR2_INET_RPC) are needed at configuration time because these
-#  options are used as dependencies for other options. And at
-#  configuration time, we are not able to retrieve the external
-#  toolchain configuration.
+#  1. a. For toolchains downloaded from the Web, Buildroot already
+#  knows their configuration, so it just downloads them and extract
+#  them in $(TOOLCHAIN_EXTERNAL_DIR).
+#
+#  1. b. For pre-installed toolchains, perform some checks on the
+#  conformity between the toolchain configuration described in the
+#  Buildroot menuconfig system, and the real configuration of the
+#  external toolchain. This is for example important to make sure that
+#  the Buildroot configuration system knows whether the toolchain
+#  supports RPC, IPv6, locales, large files, etc. Unfortunately, these
+#  things cannot be detected automatically, since the value of these
+#  options (such as BR2_INET_RPC) are needed at configuration time
+#  because these options are used as dependencies for other
+#  options. And at configuration time, we are not able to retrieve the
+#  external toolchain configuration.
 #
 #  2. Copy the libraries needed at runtime to the target directory,
 #  $(TARGET_DIR). Obviously, things such as the C library, the dynamic
@@ -55,61 +60,138 @@ LIB_EXTERNAL_LIBS+=libthread_db.so
 endif # gdbserver
 endif # ! no threads
 
-# SYSROOT_DIR selection. We first try the -print-sysroot option,
-# available in gcc 4.4.x and in some Codesourcery toolchains. If this
-# option is not available, we fallback to the value of --with-sysroot
-# as visible in CROSS-gcc -v. We don't pass any option to gcc that
-# could select a multilib variant as we want the "main" sysroot, which
-# contains all variants of the C library in the case of multilib
-# toolchains.
+# Details about sysroot directory selection.
+#
+# To find the sysroot directory:
+#
+#  * We first try the -print-sysroot option, available in gcc 4.4.x
+#    and in some Codesourcery toolchains.
+#
+#  * If this option is not available, we fallback to the value of
+#    --with-sysroot as visible in CROSS-gcc -v.
+#
+# When doing those tests, we don't pass any option to gcc that could
+# select a multilib variant (such as -march) as we want the "main"
+# sysroot, which contains all variants of the C library in the case of
+# multilib toolchains. We use the TARGET_CC_NO_SYSROOT variable, which
+# is the path of the cross-compiler, without the
+# --sysroot=$(STAGING_DIR), since what we want to find is the location
+# of the original toolchain sysroot. This "main" sysroot directory is
+# stored in SYSROOT_DIR.
+#
+# Then, multilib toolchains are a little bit more complicated, since
+# they in fact have multiple sysroots, one for each variant supported
+# by the toolchain. So we need to find the particular sysroot we're
+# interested in.
+#
+# To do so, we ask the compiler where its sysroot is by passing all
+# flags (including -march and al.), except the --sysroot flag since we
+# want to the compiler to tell us where its original sysroot
+# is. ARCH_SUBDIR will contain the subdirectory, in the main
+# SYSROOT_DIR, that corresponds to the selected architecture
+# variant. ARCH_SYSROOT_DIR will contain the full path to this
+# location.
+#
+# One might wonder why we don't just bother with ARCH_SYSROOT_DIR. The
+# fact is that in multilib toolchains, the header files are often only
+# present in the main sysroot, and only the libraries are available in
+# each variant-specific sysroot directory.
+
 TARGET_CC_NO_SYSROOT=$(filter-out --sysroot=%,$(TARGET_CC_NOCCACHE))
-SYSROOT_DIR=$(shell $(TARGET_CC_NO_SYSROOT) -print-sysroot 2>/dev/null)
-ifeq ($(SYSROOT_DIR),)
-SYSROOT_DIR=$(shell readlink -f $$(LANG=C $(TARGET_CC_NO_SYSROOT) -print-file-name=libc.a) |sed -r -e 's:usr/lib/libc\.a::;')
+
+ifeq ($(BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD),y)
+TOOLCHAIN_EXTERNAL_DEPENDENCIES = $(TOOLCHAIN_EXTERNAL_DIR)/.extracted
+else
+TOOLCHAIN_EXTERNAL_DEPENDENCIES = $(STAMP_DIR)/ext-toolchain-checked
 endif
 
-# Now, find if the toolchain specifies a sub-directory for the
-# specific architecture variant we're interested in. This is the case
-# with multilib toolchain, when the selected architecture variant is
-# not the default one. To do so, we ask the compiler by passing all
-# flags, except the --sysroot flag since we want to the compiler to
-# tell us where its original sysroot is. ARCH_SUBDIR will contain the
-# subdirectory, in the main SYSROOT_DIR, that corresponds to the
-# selected architecture variant. ARCH_SYSROOT_DIR will contain the
-# full path to this location.
-ARCH_SUBDIR=$(shell $(TARGET_CC_NO_SYSROOT) $(TARGET_CFLAGS) -print-multi-directory)
-ARCH_SYSROOT_DIR=$(SYSROOT_DIR)/$(ARCH_SUBDIR)
+ifeq ($(BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM2009Q1),y)
+TOOLCHAIN_EXTERNAL_SITE=http://www.codesourcery.com/sgpp/lite/arm/portal/package5383/public/arm-none-linux-gnueabi/
+TOOLCHAIN_EXTERNAL_SOURCE=arm-2009q3-67-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2
+else ifeq ($(BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM2010Q1),y)
+TOOLCHAIN_EXTERNAL_SITE=http://www.codesourcery.com/sgpp/lite/arm/portal/package6488/public/arm-none-linux-gnueabi/
+TOOLCHAIN_EXTERNAL_SOURCE=arm-2010q1-202-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2
+else ifeq ($(BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM201009),y)
+TOOLCHAIN_EXTERNAL_SITE=http://www.codesourcery.com/sgpp/lite/arm/portal/package7851/public/arm-none-linux-gnueabi/
+TOOLCHAIN_EXTERNAL_SOURCE=arm-2010.09-50-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2
+else ifeq ($(BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_MIPS44),y)
+TOOLCHAIN_EXTERNAL_SITE=http://www.codesourcery.com/sgpp/lite/mips/portal/package7401/public/mips-linux-gnu/
+TOOLCHAIN_EXTERNAL_SOURCE=mips-4.4-303-mips-linux-gnu-i686-pc-linux-gnu.tar.bz2
+else ifeq ($(BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_POWERPC201009),y)
+TOOLCHAIN_EXTERNAL_SITE=http://www.codesourcery.com/sgpp/lite/power/portal/package7703/public/powerpc-linux-gnu/
+TOOLCHAIN_EXTERNAL_SOURCE=freescale-2010.09-55-powerpc-linux-gnu-i686-pc-linux-gnu.tar.bz2
+else ifeq ($(BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_SH201009),y)
+TOOLCHAIN_EXTERNAL_SITE=http://www.codesourcery.com/sgpp/lite/superh/portal/package7783/public/sh-linux-gnu/
+TOOLCHAIN_EXTERNAL_SOURCE=renesas-2010.09-45-sh-linux-gnu-i686-pc-linux-gnu.tar.bz2
+else
+# A value must be set (even if unused), otherwise the
+# $(DL_DIR)/$(TOOLCHAIN_EXTERNAL_SOURCE) rule would override the main
+# $(DL_DIR) rule
+TOOLCHAIN_EXTERNAL_SOURCE=none
+endif
 
-$(STAMP_DIR)/ext-toolchain-installed:
+# Download and extraction of a toolchain
+$(DL_DIR)/$(TOOLCHAIN_EXTERNAL_SOURCE):
+	$(call DOWNLOAD,$(TOOLCHAIN_EXTERNAL_SITE),$(TOOLCHAIN_EXTERNAL_SOURCE))
+
+$(TOOLCHAIN_EXTERNAL_DIR)/.extracted: $(DL_DIR)/$(TOOLCHAIN_EXTERNAL_SOURCE)
+	mkdir -p $(@D)
+	$(INFLATE$(suffix $(TOOLCHAIN_EXTERNAL_SOURCE))) $^ | $(TAR) $(TAR_STRIP_COMPONENTS)=1 -C $(@D) $(TAR_OPTIONS) -
+	touch $@
+
+# Checks for an already installed toolchain: check the toolchain
+# location, check that it supports sysroot, and then verify that it
+# matches the configuration provided in Buildroot: ABI, C++ support,
+# type of C library and all C library features.
+$(STAMP_DIR)/ext-toolchain-checked:
 	@echo "Checking external toolchain settings"
 	$(Q)$(call check_cross_compiler_exists)
-ifeq ($(strip $(SYSROOT_DIR)),)
-	@echo "External toolchain doesn't support --sysroot. Cannot use."
-	exit 1
-endif
-ifeq ($(BR2_arm),y)
-	$(Q)$(call check_arm_abi)
-endif
-ifeq ($(BR2_INSTALL_LIBSTDCPP),y)
-	$(Q)$(call check_cplusplus)
-endif
-ifeq ($(BR2_TOOLCHAIN_EXTERNAL_UCLIBC),y)
-	$(Q)$(call check_uclibc,$(SYSROOT_DIR))
-else
-	$(Q)$(call check_glibc,$(SYSROOT_DIR))
-endif
-	mkdir -p $(TARGET_DIR)/lib
-	@echo "Copy external toolchain libraries to target..."
-	$(Q)for libs in $(LIB_EXTERNAL_LIBS); do \
-		$(call copy_toolchain_lib_root,$(ARCH_SYSROOT_DIR),$$libs,/lib,$(BR2_TOOLCHAIN_EXTERNAL_STRIP)); \
-	done
-	$(Q)for libs in $(USR_LIB_EXTERNAL_LIBS); do \
-		$(call copy_toolchain_lib_root,$(ARCH_SYSROOT_DIR),$$libs,/usr/lib,$(BR2_TOOLCHAIN_EXTERNAL_STRIP)); \
-	done
-	@echo "Copy external toolchain sysroot to staging..."
-	$(Q)$(call copy_toolchain_sysroot,$(SYSROOT_DIR),$(ARCH_SYSROOT_DIR),$(ARCH_SUBDIR))
-	# Create lib64 symbolic links if needed
-	$(Q)if [ -L $(ARCH_SYSROOT_DIR)/lib64 ] ; then \
-		$(call create_lib64_symlinks) ; \
+	$(Q)SYSROOT_DIR=`$(TARGET_CC_NO_SYSROOT) -print-sysroot 2>/dev/null` ; \
+	if test -z "$${SYSROOT_DIR}" ; then \
+		SYSROOT_DIR=`readlink -f $$(LANG=C $(TARGET_CC_NO_SYSROOT) -print-file-name=libc.a) |sed -r -e 's:usr/lib/libc\.a::;'` ; \
+	fi ; \
+	if test -z "$${SYSROOT_DIR}" ; then \
+		@echo "External toolchain doesn't support --sysroot. Cannot use." ; \
+		exit 1 ; \
+	fi ; \
+	if test x$(BR2_arm) == x"y" ; then \
+		$(call check_arm_abi) ; \
+	fi ; \
+	if test x$(BR2_INSTALL_LIBSTDCPP) == x"y" ; then \
+		$(call check_cplusplus) ; \
+	fi ; \
+	if test x$(BR2_TOOLCHAIN_EXTERNAL_UCLIBC) == x"y" ; then \
+		$(call check_uclibc,$${SYSROOT_DIR}) ; \
+	else \
+		$(call check_glibc,$${SYSROOT_DIR}) ; \
 	fi
-	@touch $@
+
+# Integration of the toolchain into Buildroot: find the main sysroot
+# and the variant-specific sysroot, then copy the needed libraries to
+# the $(TARGET_DIR) and copy the whole sysroot (libraries and headers)
+# to $(STAGING_DIR).
+$(STAMP_DIR)/ext-toolchain-installed: $(TOOLCHAIN_EXTERNAL_DEPENDENCIES)
+	$(Q)SYSROOT_DIR=`$(TARGET_CC_NO_SYSROOT) -print-sysroot 2>/dev/null` ; \
+	if test -z "$${SYSROOT_DIR}" ; then \
+		SYSROOT_DIR=`readlink -f $$(LANG=C $(TARGET_CC_NO_SYSROOT) -print-file-name=libc.a) |sed -r -e 's:usr/lib/libc\.a::;'` ; \
+	fi ; \
+	if test -z "$${SYSROOT_DIR}" ; then \
+		@echo "External toolchain doesn't support --sysroot. Cannot use." ; \
+		exit 1 ; \
+	fi ; \
+	ARCH_SUBDIR=`$(TARGET_CC_NO_SYSROOT) $(TARGET_CFLAGS) -print-multi-directory` ; \
+	ARCH_SYSROOT_DIR=$${SYSROOT_DIR}/$${ARCH_SUBDIR} ; \
+	mkdir -p $(TARGET_DIR)/lib ; \
+	echo "Copy external toolchain libraries to target..." ; \
+	for libs in $(LIB_EXTERNAL_LIBS); do \
+	 	$(call copy_toolchain_lib_root,$${ARCH_SYSROOT_DIR},$$libs,/lib,$(BR2_TOOLCHAIN_EXTERNAL_STRIP)); \
+	done ; \
+	for libs in $(USR_LIB_EXTERNAL_LIBS); do \
+	 	$(call copy_toolchain_lib_root,$${ARCH_SYSROOT_DIR},$$libs,/usr/lib,$(BR2_TOOLCHAIN_EXTERNAL_STRIP)); \
+	done ; \
+	echo "Copy external toolchain sysroot to staging..." ; \
+	$(call copy_toolchain_sysroot,$${SYSROOT_DIR},$${ARCH_SYSROOT_DIR},$${ARCH_SUBDIR}) ; \
+	if [ -L $${ARCH_SYSROOT_DIR}/lib64 ] ; then \
+		$(call create_lib64_symlinks) ; \
+	fi ; \
+	touch $@