Attempt to fix roll correction

source/imu.cpp

@@ -4,9 +4,6 @@
 
 LSM6DS3 imu(I2C_MODE, 0x6A);
 
-float rollSin = 0.0f;   // identity: no rotation
-float rollCos = 1.0f;
-
 // ─── I2C helpers ──────────────────────────────────────────────────────────────
 void imuWriteReg(uint8_t reg, uint8_t val) {
   // LSM6DS3 is on Wire1 (internal I2C, SDA=P0.17, SCL=P0.16), NOT Wire (external pins 4/5)
@@ -29,10 +26,8 @@ float readIMUTemp() {
 void calibrateGyroBias() {
   Serial.println("[CAL] Hold still...");
   double sx=0, sy=0, sz=0;
-  double sax=0, say=0;
   for (int i=0; i<BIAS_SAMPLES; i++) {
     sx += imu.readFloatGyroX(); sy += imu.readFloatGyroY(); sz += imu.readFloatGyroZ();
-    sax += imu.readFloatAccelX(); say += imu.readFloatAccelY();
     digitalWrite(LED_GREEN, (i%20 < 10)); delay(5);  // green flutter during calibration
   }
   biasGX = (float)(sx/BIAS_SAMPLES);
@@ -41,22 +36,6 @@ void calibrateGyroBias() {
   calTempC = readIMUTemp();
   angleX = angleY = accumX = accumY = 0.0f;
 
-  // Roll compensation: compute device yaw on the table from gravity's horizontal components.
-  // ax/ay are small when flat; their ratio gives the rotation angle θ.
-  // Firmware maps: screenX ← -gz, screenY ← -gy.
-  // With device rotated θ CW: screenX ← -(gz·cosθ + gy·sinθ), screenY ← -(gy·cosθ - gz·sinθ).
-  float ax_avg = (float)(sax / BIAS_SAMPLES);
-  float ay_avg = (float)(say / BIAS_SAMPLES);
-  float norm = sqrtf(ax_avg*ax_avg + ay_avg*ay_avg);
-  if (norm > 0.05f) {         // only update if we can see meaningful tilt (>~3°)
-    rollSin =  ax_avg / norm;
-    rollCos = -ay_avg / norm; // negative: gravity pulls in -Y when flat and nominal
-  } else {
-    rollSin = 0.0f;
-    rollCos = 1.0f;
-  }
-  Serial.print("[CAL] roll="); Serial.print(atan2f(rollSin, rollCos)*(180.f/PI), 1); Serial.println("deg");
-
   #ifdef FEATURE_TELEMETRY
     statRecalCount++;
     float bxr = biasGX*(PI/180.f), byr = biasGY*(PI/180.f), bzr = biasGZ*(PI/180.f);