diff --git a/conf/machine/imx6sl-warp.conf b/conf/machine/imx6sl-warp.conf
index 398220f..2f45793 100644
--- a/conf/machine/imx6sl-warp.conf
+++ b/conf/machine/imx6sl-warp.conf
@@ -34,7 +34,6 @@ IMX_DEFAULT_BSP = "mainline"
 # a binary to be used if an update is needed
 # see how-to override eMMC boot partition on the following link
 # http://git.denx.de/?p=u-boot.git;a=blob;f=board/warp/README
-IMAGE_BOOTLOADER ?= ""
 EXTRA_IMAGEDEPENDS += "u-boot"
 
 UBOOT_MACHINE ?= "warp_defconfig"
diff --git a/conf/machine/nitrogen8m.conf b/conf/machine/nitrogen8m.conf
index 73507f2..29c4ec0 100644
--- a/conf/machine/nitrogen8m.conf
+++ b/conf/machine/nitrogen8m.conf
@@ -34,8 +34,6 @@ UBOOT_SUFFIX = "bin"
 UBOOT_CONFIG ??= "sd"
 UBOOT_CONFIG[sd] = "nitrogen8m_defconfig,sdcard"
 
-IMAGE_BOOTLOADER = "imx-boot"
-
 IMXBOOT_TARGETS = "flash_evk"
 
 DDR_FIRMWARE_NAME = "\
diff --git a/conf/machine/nitrogen8mm.conf b/conf/machine/nitrogen8mm.conf
index cf18e0a..192b902 100644
--- a/conf/machine/nitrogen8mm.conf
+++ b/conf/machine/nitrogen8mm.conf
@@ -37,8 +37,6 @@ UBOOT_SUFFIX = "bin"
 UBOOT_CONFIG ??= "sd"
 UBOOT_CONFIG[sd] = "nitrogen8mm_2g_defconfig,sdcard"
 
-IMAGE_BOOTLOADER = "imx-boot"
-
 IMXBOOT_TARGETS = "flash_evk"
 
 # Set DDR FIRMWARE
diff --git a/conf/machine/nitrogen8mn.conf b/conf/machine/nitrogen8mn.conf
index f3a595d..a021532 100644
--- a/conf/machine/nitrogen8mn.conf
+++ b/conf/machine/nitrogen8mn.conf
@@ -33,8 +33,6 @@ UBOOT_SUFFIX = "bin"
 UBOOT_CONFIG ??= "sd"
 UBOOT_CONFIG[sd] = "nitrogen8_nano_8mn1gr0_defconfig,sdcard"
 
-IMAGE_BOOTLOADER = "imx-boot"
-
 IMXBOOT_TARGETS = "flash_evk"
 
 DDR_FIRMWARE_NAME = "\