--- a/browser/installer/windows/Makefile.in
+++ b/browser/installer/windows/Makefile.in
@@ -49,35 +49,25 @@ include $(topsrcdir)/toolkit/mozapps/ins
 
 CONFIG_DIR = instgen
 SFX_MODULE = $(topsrcdir)/other-licenses/7zstub/firefox/7zSD.sfx
 APP_VERSION := $(shell cat $(srcdir)/../../config/version.txt)
 DEFINES += -DAPP_VERSION=$(APP_VERSION)
 PRE_RELEASE_SUFFIX := $(shell $(PYTHON) $(topsrcdir)/config/printprereleasesuffix.py $(APP_VERSION))
 DEFINES += -DPRE_RELEASE_SUFFIX="$(PRE_RELEASE_SUFFIX)"
 
-# All script and locale files used by the Unicode version of NSIS need to be
-# converted from UTF-8 to UTF-16LE
-INSTALLER_FILES_CONV = \
+INSTALLER_FILES = \
+	app.tag \
 	nsis/installer.nsi \
 	nsis/uninstaller.nsi \
 	nsis/shared.nsh \
 	$(NULL)
 
-INSTALLER_FILES = \
-	app.tag \
-	$(NULL)
-
-# All script and locale files used by the Unicode version of NSIS need to be
-# converted from UTF-8 to UTF-16LE
-BRANDING_FILES_CONV = \
+BRANDING_FILES = \
 	branding.nsi \
-	$(NULL)
-
-BRANDING_FILES = \
 	wizHeader.bmp \
 	wizHeaderRTL.bmp \
 	wizWatermark.bmp \
 	$(NULL)
 
 DEFINES += \
 	-DAB_CD=$(AB_CD) \
 	-DMOZ_APP_NAME=$(MOZ_APP_NAME) \
@@ -90,52 +80,28 @@ include $(topsrcdir)/config/config.mk
 installer::
 	$(MAKE) -C .. installer-stage
 	$(MAKE) $(CONFIG_DIR)/setup.exe
 
 # For building the uninstaller during the application build so it can be
 # included for mar file generation.
 uninstaller::
 	$(RM) -rf $(CONFIG_DIR) && mkdir $(CONFIG_DIR)
-	for i in $(INSTALLER_FILES_CONV); do \
-	  iconv -f UTF-8 -t UTF-16LE $(srcdir)/$$i | \
-	    cat $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/utf16-le-bom.bin - > \
-	    $(CONFIG_DIR)/`basename $$i`; \
-	done
 	$(INSTALL) $(addprefix $(srcdir)/,$(INSTALLER_FILES)) $(CONFIG_DIR)
-	for i in $(BRANDING_FILES_CONV); do \
-	  iconv -f UTF-8 -t UTF-16LE $(DIST)/branding/$$i | \
-	    cat $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/utf16-le-bom.bin - > \
-	    $(CONFIG_DIR)/$$i; \
-	done
 	$(INSTALL) $(addprefix $(DIST)/branding/,$(BRANDING_FILES)) $(CONFIG_DIR)
 	$(PYTHON) $(topsrcdir)/config/Preprocessor.py -Fsubstitution $(DEFINES) $(ACDEFINES) \
-	  $(srcdir)/nsis/defines.nsi.in | iconv -f UTF-8 -t UTF-16LE | \
-	  cat $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/utf16-le-bom.bin - > \
-	  $(CONFIG_DIR)/defines.nsi
-	$(PERL) $(topsrcdir)/toolkit/mozapps/installer/windows/nsis/preprocess-locale.pl \
-	  $(topsrcdir) $(call EXPAND_LOCALE_SRCDIR,browser/locales)/installer $(AB_CD) \
-	  $(CONFIG_DIR)
+	  $(srcdir)/nsis/defines.nsi.in > $(CONFIG_DIR)/defines.nsi
+	$(PYTHON) $(topsrcdir)/toolkit/mozapps/installer/windows/nsis/preprocess-locale.py \
+	  --preprocess-locale $(topsrcdir) \
+	  $(call EXPAND_LOCALE_SRCDIR,browser/locales)/installer $(AB_CD) $(CONFIG_DIR)
 
 $(CONFIG_DIR)/setup.exe::
 	$(RM) -rf $(CONFIG_DIR) && mkdir $(CONFIG_DIR)
-	for i in $(INSTALLER_FILES_CONV); do \
-	  iconv -f UTF-8 -t UTF-16LE $(srcdir)/$$i | \
-	    cat $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/utf16-le-bom.bin - > \
-	    $(CONFIG_DIR)/`basename $$i`; \
-	done
 	$(INSTALL) $(addprefix $(srcdir)/,$(INSTALLER_FILES)) $(CONFIG_DIR)
-	for i in $(BRANDING_FILES_CONV); do \
-	  iconv -f UTF-8 -t UTF-16LE $(DIST)/branding/$$i | \
-	    cat $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/utf16-le-bom.bin - > \
-	    $(CONFIG_DIR)/$$i; \
-	done
 	$(INSTALL) $(addprefix $(DIST)/branding/,$(BRANDING_FILES)) $(CONFIG_DIR)
 	$(PYTHON) $(topsrcdir)/config/Preprocessor.py -Fsubstitution $(DEFINES) $(ACDEFINES) \
-	  $(srcdir)/nsis/defines.nsi.in | iconv -f UTF-8 -t UTF-16LE | \
-	  cat $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/utf16-le-bom.bin - > \
-	  $(CONFIG_DIR)/defines.nsi
-	$(PERL) $(topsrcdir)/toolkit/mozapps/installer/windows/nsis/preprocess-locale.pl \
-	  $(topsrcdir) $(call EXPAND_LOCALE_SRCDIR,browser/locales)/installer $(AB_CD) \
-	  $(CONFIG_DIR)
+	  $(srcdir)/nsis/defines.nsi.in > $(CONFIG_DIR)/defines.nsi
+	$(PYTHON) $(topsrcdir)/toolkit/mozapps/installer/windows/nsis/preprocess-locale.py \
+	  --preprocess-locale $(topsrcdir) \
+	  $(call EXPAND_LOCALE_SRCDIR,browser/locales)/installer $(AB_CD) $(CONFIG_DIR)
 
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/toolkit/mozapps/installer/windows/nsis/makensis.mk

--- a/configure.in
+++ b/configure.in
@@ -6437,23 +6437,16 @@ if test -n "$MOZ_INSTALLER" -a "$OS_ARCH
     if test "$MAKENSISU_VER" == "" -o \
        ! "$MAKENSISU_MAJOR_VER" == "$REQ_NSIS_MAJOR_VER" -o \
        ! "$MAKENSISU_MINOR_VER" -ge $MIN_NSIS_MINOR_VER; then
         AC_MSG_RESULT([no])
         AC_MSG_ERROR([To build the installer you must have the latest MozillaBuild or Unicode NSIS with a major version of $REQ_NSIS_MAJOR_VER and a minimum minor version of $MIN_NSIS_MINOR_VER in your path. To build without the installer reconfigure using --disable-installer.])
     fi
     AC_MSG_RESULT([yes])
     MAKENSISU="${CYGWIN_WRAPPER} $MAKENSISU"
-
-    # The Windows build for NSIS requires the iconv command line utility to
-    # convert the charset of the locale files.
-    MOZ_PATH_PROGS(HOST_ICONV, $HOST_ICONV "iconv", "")
-    if test -z "$HOST_ICONV"; then
-        AC_MSG_ERROR([To build the installer iconv is required in your path. To build without the installer reconfigure using --disable-installer.])
-    fi
 fi
 
 AC_SUBST(MOZ_INSTALLER)
 
 AC_MSG_CHECKING([for tar archiver])
 AC_CHECK_PROGS(TAR, gnutar gtar tar, "")
 if test -z "$TAR"; then
     AC_MSG_ERROR([no tar archiver found in \$PATH])

--- a/toolkit/mozapps/installer/windows/nsis/locales.nsi
+++ b/toolkit/mozapps/installer/windows/nsis/locales.nsi
@@ -31,18 +31,17 @@
 # and other provisions required by the GPL or the LGPL. If you do not delete
 # the provisions above, a recipient may use your version of this file under
 # the terms of any one of the MPL, the GPL or the LGPL.
 #
 # ***** END LICENSE BLOCK *****
 
 /**
  * "One off" locale configuration settings for RTL (e.g. locale text is read
- * right to left). Fonts should not only be specified if Win9x systems are
- * supported for East Asian locales.
+ * right to left).
  */
 
 ; Arabic
 !define ar_rtl
 
 ; Hebrew
 !define he_rtl
 

--- a/toolkit/mozapps/installer/windows/nsis/makensis.mk
+++ b/toolkit/mozapps/installer/windows/nsis/makensis.mk
@@ -40,40 +40,36 @@
 ifndef CONFIG_DIR
 $(error CONFIG_DIR must be set before including makensis.mk)
 endif
 
 ABS_CONFIG_DIR := $(shell pwd)/$(CONFIG_DIR)
 
 SFX_MODULE ?= $(error SFX_MODULE is not defined)
 
-# UTF-8 encoded files that need to be converted to UTF-16LE for NSIS
-TOOLKIT_NSIS_FILES_CONV = \
+TOOLKIT_NSIS_FILES = \
 	common.nsh \
 	locales.nsi \
 	overrides.nsh \
+	setup.ico \
 	version.nsh \
 	$(NULL)
 
 CUSTOM_NSIS_PLUGINS = \
 	AccessControl.dll \
 	AppAssocReg.dll \
 	ApplicationID.dll \
 	nsProcess.dll \
 	ShellLink.dll \
 	UAC.dll \
 	$(NULL)
 
 $(CONFIG_DIR)/setup.exe::
-	for i in $(TOOLKIT_NSIS_FILES_CONV); do \
-	  iconv -f UTF-8 -t UTF-16LE $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/$$i | \
-	    cat $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/utf16-le-bom.bin - > $(CONFIG_DIR)/$$i; \
-	done
+	$(INSTALL) $(addprefix $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/,$(TOOLKIT_NSIS_FILES)) $(CONFIG_DIR)
 	$(INSTALL) $(addprefix $(MOZILLA_DIR)/other-licenses/nsis/Plugins/,$(CUSTOM_NSIS_PLUGINS)) $(CONFIG_DIR)
-	$(INSTALL) $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/setup.ico $(CONFIG_DIR)
 	cd $(CONFIG_DIR) && $(MAKENSISU) installer.nsi
 # Support for building the uninstaller when repackaging locales
 ifeq ($(CONFIG_DIR),l10ngen)
 	cd $(CONFIG_DIR) && $(MAKENSISU) uninstaller.nsi
 endif
 
 $(CONFIG_DIR)/7zSD.sfx:
 	$(CYGWIN_WRAPPER) upx --best -o $(CONFIG_DIR)/7zSD.sfx $(SFX_MODULE)
@@ -84,17 +80,13 @@ installer::
 	$(MAKE) $(CONFIG_DIR)/7zSD.sfx
 	$(NSINSTALL) -D $(DIST)/$(PKG_INST_PATH)
 	cat $(CONFIG_DIR)/7zSD.sfx $(CONFIG_DIR)/app.tag $(CONFIG_DIR)/app.7z > "$(DIST)/$(PKG_INST_PATH)$(PKG_INST_BASENAME).exe"
 	chmod 0755 "$(DIST)/$(PKG_INST_PATH)$(PKG_INST_BASENAME).exe"
 
 # For building the uninstaller during the application build so it can be
 # included for mar file generation.
 uninstaller::
-	for i in $(TOOLKIT_NSIS_FILES_CONV); do \
-	  iconv -f UTF-8 -t UTF-16LE $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/$$i | \
-	    cat $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/utf16-le-bom.bin - > $(CONFIG_DIR)/$$i; \
-	done
+	$(INSTALL) $(addprefix $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/,$(TOOLKIT_NSIS_FILES)) $(CONFIG_DIR)
 	$(INSTALL) $(addprefix $(MOZILLA_DIR)/other-licenses/nsis/Plugins/,$(CUSTOM_NSIS_PLUGINS)) $(CONFIG_DIR)
-	$(INSTALL) $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/setup.ico $(CONFIG_DIR)
 	cd $(CONFIG_DIR) && $(MAKENSISU) uninstaller.nsi
 	$(NSINSTALL) -D $(DIST)/bin/uninstall
 	cp $(CONFIG_DIR)/helper.exe $(DIST)/bin/uninstall

new file mode 100644
--- /dev/null
+++ b/toolkit/mozapps/installer/windows/nsis/preprocess-locale.py
@@ -0,0 +1,201 @@
+# preprocess-locale.py
+# Any copyright is dedicated to the Public Domain.
+# http://creativecommons.org/publicdomain/zero/1.0/
+
+# preprocess-locale.py provides two functions depending on the arguments passed
+# to it when invoked.
+#
+# Preprocesses installer locale properties files and creates a basic NSIS nlf
+# file when invoked with --preprocess-locale.
+# 
+# Converts a UTF-8 file to a new UTF-16LE file when invoked with
+# --convert-utf8-utf16le.
+
+from codecs import BOM_UTF16_LE
+from os.path import join
+import sys
+
+def preprocess_locale(argv):
+    """
+    Validates command line arguments and displays usage if necessary
+    """
+    if len(argv) < 1 or (argv[0] != '--convert-utf8-utf16le' and argv[0] != '--preprocess-locale'):
+        sys.stderr.write("""
+preprocess-locale.py
+
+Commands:
+ --convert-utf8-utf16le - preprocesses installer locale properties files and
+                          creates a basic NSIS nlf file
+ --preprocess-locale    - converts a UTF-8 file to a new UTF-16LE file
+
+use "preprocess-locale.py <command>" to see the usage for each command
+""")
+        sys.exit(1)
+
+    if argv[0] == '--convert-utf8-utf16le':
+        if len(argv) != 3:
+            sys.stderr.write("""
+Converts a UTF-8 file to UTF-16LE
+
+Usage: preprocess-locale.py --convert-utf8-utf16le <src> <dest>
+
+Arguments:
+ <src> \tthe path to the UTF-8 source file to convert
+ <dest>\tthe path to the UTF-16LE destination file to create
+""")
+            sys.exit(1)
+	convert_utf8_utf16le(argv[1], argv[2])
+
+    if argv[0] == '--preprocess-locale':
+        if len(argv) != 5:
+            sys.stderr.write("""
+Preprocesses the installer localized properties files into the format
+required by NSIS and creates a basic NSIS nlf file.
+
+Usage: preprocess-locale.py --preprocess-locale <src> <locale> <code> <dest>
+
+Arguments:
+ <src>   \tthe path to top source directory for the toolkit source
+ <locale>\tthe path to the installer's locale files
+ <code>  \tthe locale code
+ <dest>  \tthe path to the destination directory
+""")
+            sys.exit(1)
+        preprocess_locale_files(argv[1], argv[2], argv[4], argv[4])
+
+def open_utf16le_file(path):
+    """
+    Returns an opened file object with a a UTF-16LE byte order mark.
+    """
+    fp = open(path, "w+b")
+    fp.write(BOM_UTF16_LE)
+    return fp
+
+def get_locale_strings(path, prefix, middle, add_cr):
+    """
+    Returns a string created by converting an installer locale properties file
+    into the format required by NSIS locale files.
+
+    Parameters:
+    path   - the path to the installer locale properties file to preprocess
+    prefix - a string to prefix each line with
+    middle - a string to insert between the name and value for each line
+    add_cr - boolean for whether to add an NSIS carriage return before NSIS
+             linefeeds when there isn't one already
+    """
+    output = ""
+    fp = open(path, "r")
+    for line in fp:
+        line = line.strip()
+        if line == "" or line[0] == "#":
+            continue
+
+        name, value = line.split("=", 1)
+        value = value.strip() # trim whitespace from the start and end
+        if value[-1] == "\"" and value[0] == "\"":
+            value = value[1:-1] # remove " from the start and end
+
+        if add_cr:
+            value = value.replace("\\n", "\\r\\n") # prefix $\n with $\r
+            value = value.replace("\\r\\r", "\\r") # replace $\r$\r with $\r
+
+        value = value.replace("\"", "$\\\"") # prefix " with $\
+        value = value.replace("\\r", "$\\r") # prefix \r with $
+        value = value.replace("\\n", "$\\n") # prefix \n with $
+        value = value.replace("\\t", "$\\t") # prefix \t with $
+
+        output += prefix + name.strip() + middle + " \"" + value + "\"\n"
+    fp.close()
+    return output
+
+def preprocess_locale_files(moz_dir, locale_dir, ab_cd, config_dir):
+    """
+    Preprocesses the installer localized properties files into the format
+    required by NSIS and creates a basic NSIS nlf file.
+
+    Parameters:
+    moz_dir    - the path to top source directory for the toolkit source
+    locale_dir - the path to the installer's locale files
+    ab_cd      - the locale code
+    config_dir - the path to the destination directory
+    """
+
+    # Set the language ID to 0 to make this locale the default locale. An
+    # actual ID will need to be used to create a multi-language installer
+    # (e.g. for CD distributions, etc.).
+    lang_id = "0"
+    rtl = "-"
+
+    # Check whether the locale is right to left from locales.nsi.
+    fp = open(join(moz_dir, "toolkit/mozapps/installer/windows/nsis/locales.nsi"), "r")
+    for line in fp:
+        line = line.strip()
+        if line == "!define " + ab_cd + "_rtl":
+            rtl = "RTL"
+            break
+
+    fp.close()
+
+    # Create the main NSIS language file with RTL for right to left locales
+    # along with the default codepage, font name, and font size represented
+    # by the '-' character.
+    fp = open_utf16le_file(join(config_dir, "baseLocale.nlf"))
+    fp.write((u"""# Header, don't edit
+NLF v6
+# Start editing here
+# Language ID
+%s
+# Font and size - dash (-) means default
+-
+-
+# Codepage - dash (-) means ANSI code page
+-
+# RTL - anything else than RTL means LTR
+%s
+""" % (lang_id, rtl)).encode("utf-16-le"))
+    fp.close()
+
+    # Create the main NSIS language file
+    fp = open_utf16le_file(join(config_dir, "overrideLocale.nsh"))
+    locale_strings = get_locale_strings(join(locale_dir, "override.properties"),
+                                        "LangString ^", " " + lang_id + " ", False)
+    fp.write(unicode(locale_strings, "utf-8").encode("utf-16-le"))
+    fp.close()
+
+    # Create the Modern User Interface language file
+    fp = open_utf16le_file(join(config_dir, "baseLocale.nsh"))
+    fp.write((u""";NSIS Modern User Interface - Language File
+;Compatible with Modern UI 1.68
+;Language: baseLocale (%s)
+!insertmacro MOZ_MUI_LANGUAGEFILE_BEGIN \"baseLocale\"
+!define MUI_LANGNAME \"baseLocale\"
+""" % (lang_id)).encode("utf-16-le"))
+    locale_strings = get_locale_strings(join(locale_dir, "mui.properties"),
+                                        "!define ", " ", True)
+    fp.write(unicode(locale_strings, "utf-8").encode("utf-16-le"))
+    fp.write(u"!insertmacro MOZ_MUI_LANGUAGEFILE_END\n".encode("utf-16-le"))
+    fp.close()
+
+    # Create the custom language file for our custom strings
+    fp = open_utf16le_file(join(config_dir, "customLocale.nsh"))
+    locale_strings = get_locale_strings(join(locale_dir, "custom.properties"),
+                        "LangString ", " " + lang_id + " ", True)
+    fp.write(unicode(locale_strings, "utf-8").encode("utf-16-le"))
+    fp.close()
+
+def convert_utf8_utf16le(in_file_path, out_file_path):
+    """
+    Converts a UTF-8 file to a new UTF-16LE file
+
+    Arguments:
+    in_file_path  - the path to the UTF-8 source file to convert
+    out_file_path - the path to the UTF-16LE destination file to create
+    """
+    in_fp = open(in_file_path, "r")
+    out_fp = open_utf16le_file(out_file_path)
+    out_fp.write(unicode(in_fp.read(), "utf-8").encode("utf-16-le"))
+    in_fp.close()
+    out_fp.close()
+
+if __name__ == '__main__':
+    sys.exit(preprocess_locale(sys.argv[1:]))