diff --git a/target/linux/ramips/mt7688/config-4.4 b/target/linux/ramips/mt7688/config-4.4
index 2bfd3f8f82..aad333bfdb 100644
--- a/target/linux/ramips/mt7688/config-4.4
+++ b/target/linux/ramips/mt7688/config-4.4
@@ -181,8 +181,8 @@ CONFIG_SCHED_HRTICK=y
 # CONFIG_SCHED_INFO is not set
 # CONFIG_SCSI_DMA is not set
 # CONFIG_SERIAL_8250_FSL is not set
-CONFIG_SERIAL_8250_NR_UARTS=4
-CONFIG_SERIAL_8250_RUNTIME_UARTS=4
+CONFIG_SERIAL_8250_NR_UARTS=3
+CONFIG_SERIAL_8250_RUNTIME_UARTS=3
 CONFIG_SERIAL_OF_PLATFORM=y
 CONFIG_SOC_MT7620=y
 # CONFIG_SOC_MT7621 is not set
diff --git a/target/linux/ramips/mt7688/config-4.9 b/target/linux/ramips/mt7688/config-4.9
index 92341439ee..ab29e8e0a5 100644
--- a/target/linux/ramips/mt7688/config-4.9
+++ b/target/linux/ramips/mt7688/config-4.9
@@ -183,8 +183,8 @@ CONFIG_SCHED_HRTICK=y
 # CONFIG_SCHED_INFO is not set
 # CONFIG_SCSI_DMA is not set
 # CONFIG_SERIAL_8250_FSL is not set
-CONFIG_SERIAL_8250_NR_UARTS=4
-CONFIG_SERIAL_8250_RUNTIME_UARTS=4
+CONFIG_SERIAL_8250_NR_UARTS=3
+CONFIG_SERIAL_8250_RUNTIME_UARTS=3
 CONFIG_SERIAL_OF_PLATFORM=y
 # CONFIG_SG_POOL is not set
 CONFIG_SOC_MT7620=y