diff --git a/src/posix/platform/openthread.conf.example b/src/posix/platform/openthread.conf.example
index 09668c119..a41f61a07 100644
--- a/src/posix/platform/openthread.conf.example
+++ b/src/posix/platform/openthread.conf.example
@@ -23,13 +23,12 @@ calibrated_power=11,25,1000,223344
 calibrated_power=26,26,1500,334455
 calibrated_power=26,26,700,445566
 
-
 # The radio supported channel mask that the device is allowed to be on.
 # supported_channel_mask=<RegulatoryDomain>,<ChannelMask>
-supported_channel_mask=ETSI,0x7fff800
-supported_channel_mask=FCC,0x7fff000
+supported_channel_mask=ETSI,0x3fff800
+supported_channel_mask=FCC,0x7fff800
 
 # The radio preferred channel mask that the device prefers to form on.
 # preferred_channel_mask=<RegulatoryDomain>,<ChannelMask>
-preferred_channel_mask=ETSI,0x7fff000
-preferred_channel_mask=FCC,0x7ff7000
+preferred_channel_mask=ETSI,0x1fff800
+preferred_channel_mask=FCC,0x3fff800
diff --git a/tests/scripts/expect/posix-channel-mask.exp b/tests/scripts/expect/posix-channel-mask.exp
index 43f78f78e..6e387d802 100644
--- a/tests/scripts/expect/posix-channel-mask.exp
+++ b/tests/scripts/expect/posix-channel-mask.exp
@@ -43,22 +43,22 @@ send "region US\n"
 expect_line "Done"
 
 send "channel supported\n"
-expect "0x7fff000"
+expect "0x7fff800"
 expect_line "Done"
 
 send "channel preferred\n"
-expect "0x7ff7000"
+expect "0x3fff800"
 expect_line "Done"
 
 send "region WW\n"
 expect_line "Done"
 
 send "channel supported\n"
-expect "0x7fff800"
+expect "0x3fff800"
 expect_line "Done"
 
 send "channel preferred\n"
-expect "0x7fff000"
+expect "0x1fff800"
 expect_line "Done"
 
 dispose_node 1