diff --git a/boards/xiao_nrf54l15_nrf54l15_cpuapp.conf b/boards/xiao_nrf54l15_nrf54l15_cpuapp.conf
index 0004273..f22b2e0 100644
--- a/boards/xiao_nrf54l15_nrf54l15_cpuapp.conf
+++ b/boards/xiao_nrf54l15_nrf54l15_cpuapp.conf
@@ -16,3 +16,29 @@ CONFIG_LOG_MAX_LEVEL=1
 CONFIG_LOG_BACKEND_UART=n
 CONFIG_LOG_BACKEND_SPINEL=y
 CONFIG_LOG_PROCESS_THREAD_STACK_SIZE=2048
+
+# Transmit at the nRF54L15's full +8 dBm.
+#
+# Zephyr's default is 0 dBm and the coprocessor sample never overrides it, while
+# Nordic's Matter samples set 8 -- so an RCP built from this repo was running 8 dB
+# weaker than the Matter devices talking to it. That asymmetry hurts the
+# border-router-to-device direction specifically, which is the one that matters
+# for beacon responses during a joiner's active scan.
+CONFIG_OPENTHREAD_DEFAULT_TX_POWER=8
+
+# The XIAO needs GPIO, unlike the DKs this sample targets.
+#
+# The upstream coprocessor prj.conf sets CONFIG_GPIO=n ("Disable GPIO"), which
+# is fine on a DK whose RCP has no GPIO-controlled RF hardware. This board
+# selects its antenna path with one: P2.03 powers the RF switch and P2.05
+# selects ceramic vs external, both declared as regulator-fixed nodes with
+# regulator-boot-on in the board DTS.
+#
+# With GPIO off, REGULATOR_FIXED cannot build (it depends on GPIO), so those
+# nodes get no driver and neither pin is ever driven -- the RF switch stays
+# unpowered and the border router runs with a crippled antenna path. Measured
+# -93 dBm at close range before this was found, against a -101 dBm sensitivity
+# floor.
+CONFIG_GPIO=y
+CONFIG_REGULATOR=y
+CONFIG_REGULATOR_FIXED=y