chore(nordic/ble): increase BLE TX power to +4dBm
What the developer wrote
Authored by tychovrahe
chore(nordic/ble): increase BLE TX power to +4dBm
[no changelog]
What changed, and why it matters
This commit increases the Bluetooth Low Energy (BLE) radio transmit power on Trezor's Nordic-based BLE firmware from a lower default level to +4 dBm. This is a one-line configuration change. It is not a code vulnerability in the traditional sense, but it marginally increases the physical range at which a nearby attacker could detect or attempt to interact with the device's BLE signal. The commit itself does not describe any security relevance and no security incident or advisory is supplied.
No immediate security patch is required. If the product's threat model treats BLE range extension as undesirable (e.g., to reduce physical discoverability), review whether +4 dBm is necessary for reliable user experience and consider a lower TX power or dynamic power control. Verify that bonding, privacy, and encryption requirements remain enforced at the increased range.
Security signals we found
BLE RF transmit power increased to +4 dBm
No changes to pairing, bonding, encryption, or privacy configuration
Commit marked as chore with [no changelog]
No vendor security disclosure or advisory referenced
Evidence from the diff
The change adds CONFIG_BT_CTLR_TX_PWR_PLUS_4=y in nordic/trezor/trezor-ble/prj.conf, enabling the Nordic BLE controller’s +4 dBm transmit power option. This raises RF output power compared to the previous default (likely 0 dBm or lower, depending on the Nordic SoftDevice/controller defaults in use). Higher TX power extends the discoverable range of the BLE interface and may slightly increase power consumption and RF fingerprinting exposure. It does not alter pairing, bonding, encryption, or authentication settings; existing BLE security controls (CONFIG_BT_BONDING_REQUIRED=y, CONFIG_BT_PRIVACY=y) remain in place.
Changed components
nordic/trezor/trezor-ble/prj.confNordic BLE controller radio power configurationInspect captured patch +1 / −0
diff --git a/nordic/trezor/trezor-ble/prj.conf b/nordic/trezor/trezor-ble/prj.conf
index 4a3a2bc7d..c58e007de 100644
--- a/nordic/trezor/trezor-ble/prj.conf
+++ b/nordic/trezor/trezor-ble/prj.conf
@@ -52,6 +52,7 @@ CONFIG_BT_BONDING_REQUIRED=y
CONFIG_BT_PRIVACY=y
CONFIG_BT_TINYCRYPT_ECC=y
CONFIG_BT_LL_SW_SPLIT=y
+CONFIG_BT_CTLR_TX_PWR_PLUS_4=y
#PHY update needed for updating PHY request
Why this scored 19/100
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