diff --git a/conf/bitbake.conf b/conf/bitbake.conf
index 1baecc1..de740bb 100644
--- a/conf/bitbake.conf
+++ b/conf/bitbake.conf
@@ -111,7 +111,7 @@ HOST_EXEEXT = ""
 TARGET_ARCH ?= "INVALID"
 TARGET_OS = "INVALID"
 TARGET_VENDOR = "${BUILD_VENDOR}"
-TARGET_SYS = "${TARGET_ARCH}${TARGET_VENDOR}${@['-' + bb.data.getVar('TARGET_OS', d, 1), ''][bb.data.getVar('TARGET_OS', d, 1) == ('' or 'custom')]}"
+TARGET_SYS = "${TARGET_ARCH}${TARGET_VENDOR}${@['-' + bb.data.getVar('TARGET_OS', d, 1), ''][bb.data.getVar('TARGET_OS', d, 1) in ('', 'custom')]}"
 TARGET_PREFIX = "${TARGET_SYS}-"
 TARGET_CC_ARCH = ""
 TARGET_EXEEXT = ""
@@ -119,7 +119,7 @@ TARGET_EXEEXT = ""
 SDK_ARCH ?= "${BUILD_ARCH}"
 SDK_OS ?= "${BUILD_OS}"
 SDK_VENDOR ?= "${BUILD_VENDOR}"
-SDK_SYS = "${SDK_ARCH}${SDK_VENDOR}${@['-' + bb.data.getVar('SDK_OS', d, 1), ''][bb.data.getVar('SDK_OS', d, 1) == ('' or 'custom')]}"
+SDK_SYS = "${SDK_ARCH}${SDK_VENDOR}${@['-' + bb.data.getVar('SDK_OS', d, 1), ''][bb.data.getVar('SDK_OS', d, 1) in ('', 'custom')]}"
 SDK_PREFIX = "${SDK_SYS}-"
 SDK_CC_ARCH ?= "${BUILD_CC_ARCH}"
 SDK_EXEEXT = ""