diff --git a/variants/wio-tracker-l1/platformio.ini b/variants/wio-tracker-l1/platformio.ini
index 2eb95e44..e898adc9 100644
--- a/variants/wio-tracker-l1/platformio.ini
+++ b/variants/wio-tracker-l1/platformio.ini
@@ -152,9 +152,15 @@ extra_scripts = post:create-uf2.py
 
 [env:WioTrackerL1_companion_solo_dual]
 extends = WioTrackerL1CompanionDual
+; Optimise for size, not speed: the nRF52 Arduino core defaults to -Ofast
+; (≈ -O3 + -ffast-math), which bloats flash by ~200 KB on this feature-rich
+; solo build. -Os keeps every feature, fits comfortably, and is actually safer
+; for float (no fast-math reassociation). Speed is irrelevant for the UI/mesh.
+build_unflags = -Ofast
 build_flags = ${WioTrackerL1CompanionDual.build_flags}
   -D UI_HAS_JOYSTICK_UPDOWN=1
   -D ENABLE_SCREENSHOT
+  -Os
 extra_scripts = post:create-uf2.py
 
 [env:WioTrackerL1_companion_dual_dev]