diff --git a/README.txt b/README.txt
index 89e6786361..ab22e33b77 100644
--- a/README.txt
+++ b/README.txt
@@ -225,6 +225,12 @@ Ubuntu Bash under Windows 10
   NuttX build system should deal with most that craziness for you.   But not
   all, see the section "Cygwin Build Problems" below.
 
+  WARNING:  Do not use Windows native tools with Ubuntu under Windows.  This
+  tool combination is made to work with Cygwin through the use of the
+  'cygpath -w' tool that converts paths from say '/cydrive/c/Program Files'
+  to 'C:\Program Files'.  There is, however, no corresponding tool to convert
+  '/mnt/c/Program Files' in the Ubuntu environment.
+
 INSTALLATION
 ^^^^^^^^^^^^
 
diff --git a/arch/arm/src/arm/Toolchain.defs b/arch/arm/src/arm/Toolchain.defs
index 199e118936..d713e92e5d 100644
--- a/arch/arm/src/arm/Toolchain.defs
+++ b/arch/arm/src/arm/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/arm/src/armv/Toolchain.defs
 #
-#   Copyright (C) 2012-2014, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012-2014 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -129,8 +129,6 @@ ifeq ($(CONFIG_ARM_TOOLCHAIN),CODESOURCERYW)
   MAXOPTIMIZATION ?= -O2
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -141,8 +139,6 @@ ifeq ($(CONFIG_ARM_TOOLCHAIN),DEVKITARM)
   ARCROSSDEV ?= arm-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -162,7 +158,5 @@ ifeq ($(CONFIG_ARM_TOOLCHAIN),GNU_EABIW)
   MAXOPTIMIZATION ?= -Os
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
diff --git a/arch/arm/src/armv6-m/Toolchain.defs b/arch/arm/src/armv6-m/Toolchain.defs
index b3b1d3d7c0..dfe5b9c9fd 100644
--- a/arch/arm/src/armv6-m/Toolchain.defs
+++ b/arch/arm/src/armv6-m/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/arm/src/armv6-m/Toolchain.defs
 #
-#   Copyright (C) 2013, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2013 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -107,8 +107,6 @@ ifeq ($(CONFIG_ARMV6M_TOOLCHAIN),ATOLLIC)
   ARCROSSDEV ?= arm-atollic-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   ARCHCPUFLAGS = -mcpu=cortex-m0 -mthumb -mfloat-abi=soft
 endif
@@ -136,8 +134,6 @@ ifeq ($(CONFIG_ARMV6M_TOOLCHAIN),CODEREDW)
   ARCROSSDEV ?= arm-none-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   ARCHCPUFLAGS = -mcpu=cortex-m0 -mthumb -mfloat-abi=soft
 endif
@@ -157,8 +153,6 @@ ifeq ($(CONFIG_ARMV6M_TOOLCHAIN),CODESOURCERYW)
   ARCROSSDEV ?= arm-none-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   ARCHCPUFLAGS = -mcpu=cortex-m0 -mthumb -mfloat-abi=soft
 endif
@@ -170,8 +164,6 @@ ifeq ($(CONFIG_ARMV6M_TOOLCHAIN),DEVKITARM)
   ARCROSSDEV ?= arm-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   ARCHCPUFLAGS = -mcpu=cortex-m0 -mthumb -mfloat-abi=soft
 endif
@@ -189,8 +181,6 @@ ifeq ($(CONFIG_ARMV6M_TOOLCHAIN),GNU_EABIW)
   ARCROSSDEV ?= arm-none-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   ARCHCPUFLAGS = -mcpu=cortex-m0 -mthumb -mfloat-abi=soft
 endif
diff --git a/arch/arm/src/armv7-a/Toolchain.defs b/arch/arm/src/armv7-a/Toolchain.defs
index 329abba970..8ee6efdf2a 100644
--- a/arch/arm/src/armv7-a/Toolchain.defs
+++ b/arch/arm/src/armv7-a/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/arm/src/armv7-a/Toolchain.defs
 #
-#   Copyright (C) 2013, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2013 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -129,8 +129,6 @@ ifeq ($(CONFIG_ARMV7A_TOOLCHAIN),CODESOURCERYW)
   MAXOPTIMIZATION ?= -O2
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -141,8 +139,6 @@ ifeq ($(CONFIG_ARMV7A_TOOLCHAIN),DEVKITARM)
   ARCROSSDEV ?= $(TARGET_ARCH)-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -162,7 +158,5 @@ ifeq ($(CONFIG_ARMV7A_TOOLCHAIN),GNU_EABIW)
   MAXOPTIMIZATION ?= -Os
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
diff --git a/arch/arm/src/armv7-m/Toolchain.defs b/arch/arm/src/armv7-m/Toolchain.defs
index 262f79c4de..8cfcaa3e1d 100644
--- a/arch/arm/src/armv7-m/Toolchain.defs
+++ b/arch/arm/src/armv7-m/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/arm/src/armv7-m/Toolchain.defs
 #
-#   Copyright (C) 2012-2013, 2015-2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012-2013, 2015-2016 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -167,8 +167,6 @@ ifeq ($(CONFIG_ARMV7M_TOOLCHAIN),ATOLLIC)
   ARCHCPUFLAGS = $(TOOLCHAIN_MCPU) -mthumb $(TOOLCHAIN_MFLOAT)
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -205,8 +203,6 @@ ifeq ($(CONFIG_ARMV7M_TOOLCHAIN),CODEREDW)
   ARCHCPUFLAGS = $(TOOLCHAIN_MCPU) -mthumb $(TOOLCHAIN_MFLOAT)
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -228,8 +224,6 @@ ifeq ($(CONFIG_ARMV7M_TOOLCHAIN),CODESOURCERYW)
   ARCHCPUFLAGS = $(TOOLCHAIN_MCPU) -mthumb $(TOOLCHAIN_MFLOAT)
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -240,8 +234,6 @@ ifeq ($(CONFIG_ARMV7M_TOOLCHAIN),DEVKITARM)
   ARCROSSDEV ?= arm-none-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   ARCHCPUFLAGS = $(TOOLCHAIN_MCPU) -mthumb $(TOOLCHAIN_MFLOAT)
 endif
@@ -264,8 +256,6 @@ ifeq ($(CONFIG_ARMV7M_TOOLCHAIN),GNU_EABIW)
   ARCHCPUFLAGS = $(TOOLCHAIN_MCPU) -mthumb $(TOOLCHAIN_MFLOAT)
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -276,8 +266,6 @@ ifeq ($(CONFIG_ARMV7M_TOOLCHAIN),RAISONANCE)
   ARCROSSDEV ?= arm-none-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   ARCHCPUFLAGS = $(TOOLCHAIN_MCPU) -mthumb $(TOOLCHAIN_MFLOAT)
 endif
diff --git a/arch/arm/src/armv7-r/Toolchain.defs b/arch/arm/src/armv7-r/Toolchain.defs
index 09aab78440..f1eb9db817 100644
--- a/arch/arm/src/armv7-r/Toolchain.defs
+++ b/arch/arm/src/armv7-r/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/arm/src/armv7-r/Toolchain.defs
 #
-#   Copyright (C) 2015, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2015 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -129,8 +129,6 @@ ifeq ($(CONFIG_ARMV7R_TOOLCHAIN),CODESOURCERYW)
   MAXOPTIMIZATION ?= -O2
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -141,8 +139,6 @@ ifeq ($(CONFIG_ARMV7R_TOOLCHAIN),DEVKITARM)
   ARCROSSDEV ?= $(TARGET_ARCH)-eabi-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
@@ -162,7 +158,5 @@ ifeq ($(CONFIG_ARMV7R_TOOLCHAIN),GNU_EABIW)
   MAXOPTIMIZATION ?= -Os
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
diff --git a/arch/avr/src/avr/Toolchain.defs b/arch/avr/src/avr/Toolchain.defs
index eea11e441a..7503086fb0 100644
--- a/arch/avr/src/avr/Toolchain.defs
+++ b/arch/avr/src/avr/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/avr/src/avr/Toolchain.defs
 #
-#   Copyright (C) 2012-2013, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012-2013 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -134,8 +134,6 @@ ifeq ($(_WINAVR),1)
   CROSSDEV ?= avr-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   MAXOPTIMIZATION ?= -O2
   LDFLAGS += -nostartfiles -nodefaultlibs
diff --git a/arch/avr/src/avr32/Toolchain.defs b/arch/avr/src/avr32/Toolchain.defs
index 68f9c7045b..b0a40e34b3 100644
--- a/arch/avr/src/avr32/Toolchain.defs
+++ b/arch/avr/src/avr32/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/avr/src/avr32/Toolchain.defs
 #
-#   Copyright (C) 2012, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -62,8 +62,6 @@ endif
 ifeq ($(CONFIG_AVR32_TOOLCHAIN),AVRTOOLSW)
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 else
   # AVR Tools or avr32-toolchain from https://github.com/jsnyder/avr32-toolchain
diff --git a/arch/mips/src/mips32/Toolchain.defs b/arch/mips/src/mips32/Toolchain.defs
index 3e2947a7e1..cee45311d8 100644
--- a/arch/mips/src/mips32/Toolchain.defs
+++ b/arch/mips/src/mips32/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/mips/src/mips32/Toolchain.defs
 #
-#   Copyright (C) 2012-2013, 2015, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012-2013, 2015 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -178,8 +178,6 @@ ifeq ($(CONFIG_MIPS32_TOOLCHAIN),MICROCHIPW_XC32)
   CROSSDEV ?= xc32-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 ifeq ($(CONFIG_MIPS32_TOOLCHAIN_MICROCHIP_XC32_LICENSED),y)
   MAXOPTIMIZATION ?= -O2
@@ -195,8 +193,6 @@ ifeq ($(CONFIG_MIPS32_TOOLCHAIN),MICROCHIPW)
   CROSSDEV ?= pic32-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   MAXOPTIMIZATION ?= -O2
   ARCHCPUFLAGS = -mprocessor=$(MIPS_MPROCESSOR) $(MIPS_MICROMIPS) -mno-float -mlong32 -membedded-data
@@ -223,8 +219,6 @@ ifeq ($(CONFIG_MIPS32_TOOLCHAIN),MICROCHIPW_LITE)
   # CROSSDEV ?= xc32-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   # MAXOPTIMIZATION ?= -O2
   ARCHCPUFLAGS = -mprocessor=$(MIPS_MPROCESSOR) $(MIPS_MICROMIPS) -mno-float -mlong32 -membedded-data
@@ -251,8 +245,6 @@ ifeq ($(CONFIG_MIPS32_TOOLCHAIN),PINGUINOW)
   CROSSDEV ?= p32-
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
   MAXOPTIMIZATION ?= -O2
   ARCHCPUFLAGS = -mlong32 -membedded-data -msoft-float -march=$(MIPS_MARCH) $(MIPS_MICROMIPS) -EL
diff --git a/arch/misoc/src/lm32/Toolchain.defs b/arch/misoc/src/lm32/Toolchain.defs
index f7c7c1adf9..f59fa1ab45 100644
--- a/arch/misoc/src/lm32/Toolchain.defs
+++ b/arch/misoc/src/lm32/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/misco/src/lm32/Toolchain.defs
 #
-#   Copyright (C) 2016-2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2016 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -100,7 +100,5 @@ ifeq ($(CONFIG_LM32_TOOLCHAIN),GNUW)
   MAXOPTIMIZATION ?= -Os
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
diff --git a/arch/z80/src/ez80/Toolchain.defs b/arch/z80/src/ez80/Toolchain.defs
index 257a37d995..bc68e4782d 100644
--- a/arch/z80/src/ez80/Toolchain.defs
+++ b/arch/z80/src/ez80/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/z80/src/ez80/Toolchain.defs
 #
-#   Copyright (C) 2012, 2016-2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012, 2016 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -44,6 +44,4 @@ CONFIG_EZ80_TOOLCHAIN ?= ZDSII
 
 ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
   WINTOOL = y
-else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-  WINTOOL = y
 endif
diff --git a/arch/z80/src/z180/Toolchain.defs b/arch/z80/src/z180/Toolchain.defs
index ed57fff794..cf97558ffc 100644
--- a/arch/z80/src/z180/Toolchain.defs
+++ b/arch/z80/src/z180/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/z80/src/z180/Toolchain.defs
 #
-#   Copyright (C) 2012, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -69,8 +69,6 @@ endif
 ifeq ($(CONFIG_AVR_TOOLCHAIN),SDCCWIN32)
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif
 
diff --git a/arch/z80/src/z8/Toolchain.defs b/arch/z80/src/z8/Toolchain.defs
index e1f5cb6420..9aaf1b89ce 100644
--- a/arch/z80/src/z8/Toolchain.defs
+++ b/arch/z80/src/z8/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/z80/src/z8/Toolchain.defs
 #
-#   Copyright (C) 2012, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -44,6 +44,4 @@ CONFIG_Z8_TOOLCHAIN ?= ZDSII
 
 ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
   WINTOOL = y
-else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-  WINTOOL = y
 endif
diff --git a/arch/z80/src/z80/Toolchain.defs b/arch/z80/src/z80/Toolchain.defs
index 9c0776247a..90fc9944ad 100644
--- a/arch/z80/src/z80/Toolchain.defs
+++ b/arch/z80/src/z80/Toolchain.defs
@@ -1,7 +1,7 @@
 ############################################################################
 # arch/z80/src/z80/Toolchain.defs
 #
-#   Copyright (C) 2012, 2017 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2012 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -69,8 +69,6 @@ endif
 ifeq ($(CONFIG_AVR_TOOLCHAIN),SDCCWIN32)
   ifeq ($(CONFIG_WINDOWS_CYGWIN),y)
     WINTOOL = y
-  else ifeq ($(CONFIG_WINDOWS_UBUNTU),y)
-    WINTOOL = y
   endif
 endif