diff --git a/conf/machine/include/davinci.inc b/conf/machine/include/davinci.inc
index 6de64839..62ca6887 100644
--- a/conf/machine/include/davinci.inc
+++ b/conf/machine/include/davinci.inc
@@ -5,7 +5,7 @@ MACHINE_KERNEL_PR = "r54"
 
 KERNEL_IMAGETYPE = "zImage"
 
-PREFERRED_PROVIDER_virtual/kernel = "linux-ti-staging"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-ti-staging"
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot-ti-staging"
 PREFERRED_PROVIDER_u-boot = "u-boot-ti-staging"
 
diff --git a/conf/machine/include/k3.inc b/conf/machine/include/k3.inc
index 0c16d968..765e0ee3 100644
--- a/conf/machine/include/k3.inc
+++ b/conf/machine/include/k3.inc
@@ -10,7 +10,7 @@ BBMULTICONFIG += "k3r5"
 # Increase this everytime you change something in the kernel
 MACHINE_KERNEL_PR = "r0"
 
-PREFERRED_PROVIDER_virtual/kernel = "linux-ti-staging"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-ti-staging"
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot-ti-staging"
 PREFERRED_PROVIDER_u-boot = "u-boot-ti-staging"
 
diff --git a/conf/machine/include/keystone.inc b/conf/machine/include/keystone.inc
index ef33975f..e7ea9758 100644
--- a/conf/machine/include/keystone.inc
+++ b/conf/machine/include/keystone.inc
@@ -4,7 +4,7 @@ SOC_FAMILY_append = ":keystone"
 DEFAULTTUNE ?= "armv7athf-neon"
 require conf/machine/include/tune-cortexa15.inc
 
-PREFERRED_PROVIDER_virtual/kernel = "linux-ti-staging"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-ti-staging"
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot-ti-staging"
 PREFERRED_PROVIDER_u-boot = "u-boot-ti-staging"
 
diff --git a/conf/machine/include/omap-a15.inc b/conf/machine/include/omap-a15.inc
index 7600126d..c22e6dd6 100644
--- a/conf/machine/include/omap-a15.inc
+++ b/conf/machine/include/omap-a15.inc
@@ -7,7 +7,7 @@ require conf/machine/include/tune-cortexa15.inc
 # Increase this everytime you change something in the kernel
 MACHINE_KERNEL_PR = "r7"
 
-PREFERRED_PROVIDER_virtual/kernel = "linux-ti-staging"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-ti-staging"
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot-ti-staging"
 PREFERRED_PROVIDER_u-boot = "u-boot-ti-staging"
 
diff --git a/conf/machine/include/omap3.inc b/conf/machine/include/omap3.inc
index 489f1f9a..5696c82d 100644
--- a/conf/machine/include/omap3.inc
+++ b/conf/machine/include/omap3.inc
@@ -22,7 +22,7 @@ MACHINE_KERNEL_PR = "r127"
 KERNEL_IMAGETYPE = "zImage"
 
 # Default providers, may need to override for specific machines
-PREFERRED_PROVIDER_virtual/kernel = "linux-ti-staging"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-ti-staging"
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot-ti-staging"
 PREFERRED_PROVIDER_u-boot = "u-boot-ti-staging"
 
diff --git a/conf/machine/include/omap4.inc b/conf/machine/include/omap4.inc
index d9706066..cbca267c 100644
--- a/conf/machine/include/omap4.inc
+++ b/conf/machine/include/omap4.inc
@@ -4,7 +4,7 @@ SOC_FAMILY_append = ":omap4"
 DEFAULTTUNE ?= "armv7athf-neon"
 require conf/machine/include/tune-cortexa9.inc
 
-PREFERRED_PROVIDER_virtual/kernel = "linux-ti-staging"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-ti-staging"
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot-ti-staging"
 PREFERRED_PROVIDER_u-boot = "u-boot-ti-staging"
 
diff --git a/conf/machine/include/ti33x.inc b/conf/machine/include/ti33x.inc
index db1df043..bf9b5570 100644
--- a/conf/machine/include/ti33x.inc
+++ b/conf/machine/include/ti33x.inc
@@ -20,7 +20,7 @@ MACHINE_GUI_CLASS = "bigscreen"
 MACHINE_KERNEL_PR = "r22"
 
 # Default providers, may need to override for specific machines
-PREFERRED_PROVIDER_virtual/kernel = "linux-ti-staging"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-ti-staging"
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot-ti-staging"
 PREFERRED_PROVIDER_u-boot = "u-boot-ti-staging"
 
diff --git a/conf/machine/include/ti43x.inc b/conf/machine/include/ti43x.inc
index e2aaf38c..5d6ea412 100644
--- a/conf/machine/include/ti43x.inc
+++ b/conf/machine/include/ti43x.inc
@@ -20,7 +20,7 @@ MACHINE_GUI_CLASS = "bigscreen"
 MACHINE_KERNEL_PR = "r3"
 
 # Default providers, may need to override for specific machines
-PREFERRED_PROVIDER_virtual/kernel = "linux-ti-staging"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-ti-staging"
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot-ti-staging"
 PREFERRED_PROVIDER_u-boot = "u-boot-ti-staging"
 
diff --git a/conf/machine/omapl137-evm.conf b/conf/machine/omapl137-evm.conf
index a8039f31..207b213a 100644
--- a/conf/machine/omapl137-evm.conf
+++ b/conf/machine/omapl137-evm.conf
@@ -6,7 +6,7 @@ require conf/machine/include/davinci.inc
 require conf/machine/include/omapl137.inc
 
 # HACK: The omapl137 family does not have linux kernel support.
-PREFERRED_PROVIDER_virtual/kernel = "linux-dummy"
+PREFERRED_PROVIDER_virtual/kernel ?= "linux-dummy"
 EXTRA_IMAGEDEPENDS = ""
 
 IMAGE_FSTYPES = "tar.xz"