diff --git a/conf/firmwares/subsystems/shared/imu_analog.makefile b/conf/firmwares/subsystems/shared/imu_analog.makefile
index c0d084b64f7..511463438b2 100644
--- a/conf/firmwares/subsystems/shared/imu_analog.makefile
+++ b/conf/firmwares/subsystems/shared/imu_analog.makefile
@@ -89,9 +89,14 @@ $(error Not implemented for the stm32 yet... should be trivial, just do it...)
 
 endif
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(imu_CFLAGS)
-ap.srcs += $(imu_srcs)
 
-test_imu.CFLAG += $(imu_CFLAGS)
-test_imu.srcs += $(imu_srcs)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(imu_CFLAGS)
+$(TARGET).srcs += $(imu_srcs)
+endif
+
+#
+# NPS simulator
+#
+include $(CFG_SHARED)/imu_nps.makefile
diff --git a/conf/firmwares/subsystems/shared/imu_apogee.makefile b/conf/firmwares/subsystems/shared/imu_apogee.makefile
index 0f8bfcf272b..b47f862f72d 100644
--- a/conf/firmwares/subsystems/shared/imu_apogee.makefile
+++ b/conf/firmwares/subsystems/shared/imu_apogee.makefile
@@ -16,11 +16,12 @@ IMU_APOGEE_CFLAGS += -DIMU_APOGEE_I2C_DEV=$(IMU_APOGEE_I2C_DEV)
 IMU_APOGEE_SRCS += peripherals/mpu60x0.c
 IMU_APOGEE_SRCS += peripherals/mpu60x0_i2c.c
 
-ap.CFLAGS += $(IMU_APOGEE_CFLAGS)
-ap.srcs   += $(IMU_APOGEE_SRCS)
 
-test_imu.CFLAGS += $(IMU_APOGEE_CFLAGS)
-test_imu.srcs   += $(IMU_APOGEE_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_APOGEE_CFLAGS)
+$(TARGET).srcs += $(IMU_APOGEE_SRCS)
+endif
 
 #
 # Simulator
diff --git a/conf/firmwares/subsystems/shared/imu_ardrone2.makefile b/conf/firmwares/subsystems/shared/imu_ardrone2.makefile
index cc7fa61c834..5f7a9efe9b4 100644
--- a/conf/firmwares/subsystems/shared/imu_ardrone2.makefile
+++ b/conf/firmwares/subsystems/shared/imu_ardrone2.makefile
@@ -11,9 +11,13 @@ imu_srcs   += $(SRC_SUBSYSTEMS)/imu/imu_ardrone2_raw.c
 imu_srcs   += $(SRC_BOARD)/navdata.c
 endif
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(imu_CFLAGS)
-ap.srcs += $(imu_srcs)
+
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(imu_CFLAGS)
+$(TARGET).srcs += $(imu_srcs)
+endif
+
 
 # Set the AHRS propegation frequencies
 AHRS_PROPAGATE_FREQUENCY ?= 200
diff --git a/conf/firmwares/subsystems/shared/imu_aspirin2_i2c.makefile b/conf/firmwares/subsystems/shared/imu_aspirin2_i2c.makefile
index 9a2d152c49e..78f77d6cb53 100644
--- a/conf/firmwares/subsystems/shared/imu_aspirin2_i2c.makefile
+++ b/conf/firmwares/subsystems/shared/imu_aspirin2_i2c.makefile
@@ -27,11 +27,12 @@ IMU_ASPIRIN2_I2C_DEV_LOWER=$(shell echo $(IMU_ASPIRIN2_I2C_DEV) | tr A-Z a-z)
 IMU_ASPIRIN2_CFLAGS += -DIMU_ASPIRIN2_I2C_DEV=$(IMU_ASPIRIN2_I2C_DEV_LOWER)
 IMU_ASPIRIN2_CFLAGS += -DUSE_$(IMU_ASPIRIN2_I2C_DEV_UPPER)
 
-ap.CFLAGS += $(IMU_ASPIRIN2_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN2_SRCS)
 
-test_imu.CFLAGS += $(IMU_ASPIRIN2_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN2_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN2_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN2_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_aspirin_i2c_v1.0.makefile b/conf/firmwares/subsystems/shared/imu_aspirin_i2c_v1.0.makefile
index a67c9ddda67..42da221a965 100644
--- a/conf/firmwares/subsystems/shared/imu_aspirin_i2c_v1.0.makefile
+++ b/conf/firmwares/subsystems/shared/imu_aspirin_i2c_v1.0.makefile
@@ -24,9 +24,8 @@ include $(CFG_SHARED)/imu_aspirin_i2c_common.makefile
 
 IMU_ASPIRIN_CFLAGS += -DIMU_ASPIRIN_VERSION_1_0
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(IMU_ASPIRIN_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN_SRCS)
-
-test_imu.CFLAGS += $(IMU_ASPIRIN_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN_SRCS)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_aspirin_i2c_v1.5.makefile b/conf/firmwares/subsystems/shared/imu_aspirin_i2c_v1.5.makefile
index 08f387621fd..d3234a4bbd9 100644
--- a/conf/firmwares/subsystems/shared/imu_aspirin_i2c_v1.5.makefile
+++ b/conf/firmwares/subsystems/shared/imu_aspirin_i2c_v1.5.makefile
@@ -24,9 +24,8 @@ include $(CFG_SHARED)/imu_aspirin_i2c_common.makefile
 
 IMU_ASPIRIN_CFLAGS += -DIMU_ASPIRIN_VERSION_1_5
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(IMU_ASPIRIN_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN_SRCS)
-
-test_imu.CFLAGS += $(IMU_ASPIRIN_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN_SRCS)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_aspirin_v1.0.makefile b/conf/firmwares/subsystems/shared/imu_aspirin_v1.0.makefile
index ec0d54fe9b8..7992397da4b 100644
--- a/conf/firmwares/subsystems/shared/imu_aspirin_v1.0.makefile
+++ b/conf/firmwares/subsystems/shared/imu_aspirin_v1.0.makefile
@@ -24,9 +24,8 @@ include $(CFG_SHARED)/imu_aspirin_common.makefile
 
 IMU_ASPIRIN_CFLAGS += -DIMU_ASPIRIN_VERSION_1_0
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(IMU_ASPIRIN_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN_SRCS)
-
-test_imu.CFLAGS += $(IMU_ASPIRIN_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN_SRCS)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_aspirin_v1.5.makefile b/conf/firmwares/subsystems/shared/imu_aspirin_v1.5.makefile
index 1d0a4e5f24c..03e04662b47 100644
--- a/conf/firmwares/subsystems/shared/imu_aspirin_v1.5.makefile
+++ b/conf/firmwares/subsystems/shared/imu_aspirin_v1.5.makefile
@@ -24,9 +24,8 @@ include $(CFG_SHARED)/imu_aspirin_common.makefile
 
 IMU_ASPIRIN_CFLAGS += -DIMU_ASPIRIN_VERSION_1_5
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(IMU_ASPIRIN_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN_SRCS)
-
-test_imu.CFLAGS += $(IMU_ASPIRIN_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN_SRCS)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_aspirin_v2.1.makefile b/conf/firmwares/subsystems/shared/imu_aspirin_v2.1.makefile
index e34869ff12c..0574132a1df 100644
--- a/conf/firmwares/subsystems/shared/imu_aspirin_v2.1.makefile
+++ b/conf/firmwares/subsystems/shared/imu_aspirin_v2.1.makefile
@@ -38,8 +38,8 @@
 
 include $(CFG_SHARED)/imu_aspirin_v2_common.makefile
 
-ap.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN_2_SRCS)
-
-test_imu.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN_2_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN_2_SRCS)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_aspirin_v2.2.makefile b/conf/firmwares/subsystems/shared/imu_aspirin_v2.2.makefile
index fd4a9e97f34..db51d1c0750 100644
--- a/conf/firmwares/subsystems/shared/imu_aspirin_v2.2.makefile
+++ b/conf/firmwares/subsystems/shared/imu_aspirin_v2.2.makefile
@@ -53,11 +53,8 @@ else ifeq ($(ARCH), stm32)
 IMU_ASPIRIN_2_CFLAGS += -DUSE_SPI_SLAVE3
 endif
 
-ap.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN_2_SRCS)
-
-test_imu.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN_2_SRCS)
-
-test_ahrs.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-test_ahrs.srcs   += $(IMU_ASPIRIN_2_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN_2_SRCS)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_b2_v1.0.makefile b/conf/firmwares/subsystems/shared/imu_b2_v1.0.makefile
index a24859ff39e..59315ec83fa 100644
--- a/conf/firmwares/subsystems/shared/imu_b2_v1.0.makefile
+++ b/conf/firmwares/subsystems/shared/imu_b2_v1.0.makefile
@@ -57,9 +57,8 @@ endif
 
 endif #NO_MAG
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(imu_CFLAGS)
-ap.srcs += $(imu_srcs)
-
-test_imu.CFLAGS += $(imu_CFLAGS)
-test_imu.srcs += $(imu_srcs)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(imu_CFLAGS)
+$(TARGET).srcs += $(imu_srcs)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_b2_v1.1.makefile b/conf/firmwares/subsystems/shared/imu_b2_v1.1.makefile
index 27441696628..cb6a06ffd04 100644
--- a/conf/firmwares/subsystems/shared/imu_b2_v1.1.makefile
+++ b/conf/firmwares/subsystems/shared/imu_b2_v1.1.makefile
@@ -57,9 +57,8 @@ imu_CFLAGS += -DMS2100_SLAVE_IDX=4
 imu_CFLAGS += -DMS2100_SPI_DEV=spi2
 endif
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(imu_CFLAGS)
-ap.srcs += $(imu_srcs)
-
-test_imu.CFLAGS += $(imu_CFLAGS)
-test_imu.srcs += $(imu_srcs)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(imu_CFLAGS)
+$(TARGET).srcs += $(imu_srcs)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_b2_v1.2.makefile b/conf/firmwares/subsystems/shared/imu_b2_v1.2.makefile
index 6e8cceb0a57..57f201d6a52 100644
--- a/conf/firmwares/subsystems/shared/imu_b2_v1.2.makefile
+++ b/conf/firmwares/subsystems/shared/imu_b2_v1.2.makefile
@@ -50,9 +50,8 @@ else ifeq ($(ARCH), stm32)
 imu_CFLAGS += -DIMU_B2_I2C_DEV=i2c2 -DUSE_I2C2
 endif
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(imu_CFLAGS)
-ap.srcs += $(imu_srcs)
-
-test_imu.CFLAGS += $(imu_CFLAGS)
-test_imu.srcs += $(imu_srcs)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(imu_CFLAGS)
+$(TARGET).srcs += $(imu_srcs)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_bebop.makefile b/conf/firmwares/subsystems/shared/imu_bebop.makefile
index 4df31b36638..9d4d0f70790 100644
--- a/conf/firmwares/subsystems/shared/imu_bebop.makefile
+++ b/conf/firmwares/subsystems/shared/imu_bebop.makefile
@@ -37,11 +37,11 @@ BEBOP_MPU_I2C_DEV_LOWER=$(shell echo $(BEBOP_MPU_I2C_DEV) | tr A-Z a-z)
 IMU_CFLAGS  += -DBEBOP_MAG_I2C_DEV=$(BEBOP_MAG_I2C_DEV_LOWER) -DBEBOP_MPU_I2C_DEV=$(BEBOP_MPU_I2C_DEV_LOWER)
 IMU_CFLAGS  += -DUSE_$(BEBOP_MAG_I2C_DEV_UPPER)=1 -DUSE_$(BEBOP_MPU_I2C_DEV_UPPER)=1
 
-ap.CFLAGS += $(IMU_CFLAGS)
-ap.srcs   += $(IMU_SRCS)
-
-test_imu.CFLAGS += $(IMU_CFLAGS)
-test_imu.srcs   += $(IMU_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_CFLAGS)
+$(TARGET).srcs += $(IMU_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_drotek_10dof_v2.makefile b/conf/firmwares/subsystems/shared/imu_drotek_10dof_v2.makefile
index 6bc352a6cde..fd9ae23592f 100644
--- a/conf/firmwares/subsystems/shared/imu_drotek_10dof_v2.makefile
+++ b/conf/firmwares/subsystems/shared/imu_drotek_10dof_v2.makefile
@@ -73,14 +73,11 @@ IMU_DROTEK_2_CFLAGS += -DDROTEK_2_I2C_DEV=$(DROTEK_2_I2C_DEV_LOWER)
 IMU_DROTEK_2_CFLAGS += -DUSE_$(DROTEK_2_I2C_DEV_UPPER)
 
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-
-ap.CFLAGS += $(IMU_DROTEK_2_CFLAGS)
-ap.srcs   += $(IMU_DROTEK_2_SRCS)
-
-test_imu.CFLAGS += $(IMU_DROTEK_2_CFLAGS)
-test_imu.srcs   += $(IMU_DROTEK_2_SRCS)
-
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_DROTEK_2_CFLAGS)
+$(TARGET).srcs += $(IMU_DROTEK_2_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_gl1.makefile b/conf/firmwares/subsystems/shared/imu_gl1.makefile
index d822ab39cc3..07e9a07dd85 100644
--- a/conf/firmwares/subsystems/shared/imu_gl1.makefile
+++ b/conf/firmwares/subsystems/shared/imu_gl1.makefile
@@ -41,12 +41,11 @@ GL1_I2C_DEV_LOWER=$(shell echo $(GL1_I2C_DEV) | tr A-Z a-z)
 IMU_GL1_CFLAGS += -DGL1_I2C_DEV=$(GL1_I2C_DEV_LOWER)
 IMU_GL1_CFLAGS += -DUSE_$(GL1_I2C_DEV_UPPER)
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-ap.CFLAGS += $(IMU_GL1_CFLAGS)
-ap.srcs   += $(IMU_GL1_SRCS)
-
-test_imu.CFLAGS += $(IMU_GL1_CFLAGS)
-test_imu.srcs   += $(IMU_GL1_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_GL1_CFLAGS)
+$(TARGET).srcs += $(IMU_GL1_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_hbmini.makefile b/conf/firmwares/subsystems/shared/imu_hbmini.makefile
index 88b42179459..ce58f773110 100644
--- a/conf/firmwares/subsystems/shared/imu_hbmini.makefile
+++ b/conf/firmwares/subsystems/shared/imu_hbmini.makefile
@@ -24,8 +24,11 @@ IMU_HBMINI_CFLAGS += -DMAX1168_EOC_VIC_SLOT=11
 IMU_HBMINI_SRCS += peripherals/max1168.c
 IMU_HBMINI_SRCS += $(SRC_ARCH)/peripherals/max1168_arch.c
 
-ap.CFLAGS += $(IMU_HBMINI_CFLAGS)
-ap.srcs   += $(IMU_HBMINI_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_HBMINI_CFLAGS)
+$(TARGET).srcs += $(IMU_HBMINI_SRCS)
+endif
 
 #
 # Simulator
diff --git a/conf/firmwares/subsystems/shared/imu_krooz_sd.makefile b/conf/firmwares/subsystems/shared/imu_krooz_sd.makefile
index cb595ee0fd1..a5fc6862816 100644
--- a/conf/firmwares/subsystems/shared/imu_krooz_sd.makefile
+++ b/conf/firmwares/subsystems/shared/imu_krooz_sd.makefile
@@ -18,11 +18,11 @@ IMU_KROOZ_SRCS += peripherals/mpu60x0.c
 IMU_KROOZ_SRCS += peripherals/mpu60x0_i2c.c
 IMU_KROOZ_SRCS += peripherals/hmc58xx.c
 
-ap.CFLAGS += $(IMU_KROOZ_CFLAGS)
-ap.srcs   += $(IMU_KROOZ_SRCS)
-
-test_imu.CFLAGS += $(IMU_KROOZ_CFLAGS)
-test_imu.srcs   += $(IMU_KROOZ_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_KROOZ_CFLAGS)
+$(TARGET).srcs += $(IMU_KROOZ_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_krooz_sd_memsic.makefile b/conf/firmwares/subsystems/shared/imu_krooz_sd_memsic.makefile
index db7e30645a3..3d1487155a0 100644
--- a/conf/firmwares/subsystems/shared/imu_krooz_sd_memsic.makefile
+++ b/conf/firmwares/subsystems/shared/imu_krooz_sd_memsic.makefile
@@ -23,11 +23,11 @@ IMU_KROOZ_SRCS += peripherals/mpu60x0.c
 IMU_KROOZ_SRCS += peripherals/mpu60x0_i2c.c
 IMU_KROOZ_SRCS += peripherals/hmc58xx.c
 
-ap.CFLAGS += $(IMU_KROOZ_CFLAGS)
-ap.srcs   += $(IMU_KROOZ_SRCS)
-
-test_imu.CFLAGS += $(IMU_KROOZ_CFLAGS)
-test_imu.srcs   += $(IMU_KROOZ_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_KROOZ_CFLAGS)
+$(TARGET).srcs += $(IMU_KROOZ_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_lisa_m_or_mx_v2.1.makefile b/conf/firmwares/subsystems/shared/imu_lisa_m_or_mx_v2.1.makefile
index b9696ba115d..1ada70b3718 100644
--- a/conf/firmwares/subsystems/shared/imu_lisa_m_or_mx_v2.1.makefile
+++ b/conf/firmwares/subsystems/shared/imu_lisa_m_or_mx_v2.1.makefile
@@ -63,14 +63,12 @@ IMU_ASPIRIN_2_CFLAGS += -DUSE_SPI_SLAVE2
 # SLAVE3 is on PC13, which is the baro CS
 IMU_ASPIRIN_2_CFLAGS += -DUSE_SPI_SLAVE3
 
-ap.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN_2_SRCS)
 
-test_imu.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN_2_SRCS)
-
-test_ahrs.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-test_ahrs.srcs   += $(IMU_ASPIRIN_2_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN_2_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_lisa_s_v1.0.makefile b/conf/firmwares/subsystems/shared/imu_lisa_s_v1.0.makefile
index 48caa3b4872..2c9255e1ebc 100644
--- a/conf/firmwares/subsystems/shared/imu_lisa_s_v1.0.makefile
+++ b/conf/firmwares/subsystems/shared/imu_lisa_s_v1.0.makefile
@@ -61,11 +61,11 @@ IMU_ASPIRIN_2_CFLAGS += -DUSE_SPI_SLAVE0
 # SLAVE1 is on PC4, which is the baro CS
 IMU_ASPIRIN_2_CFLAGS += -DUSE_SPI_SLAVE1
 
-ap.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-ap.srcs   += $(IMU_ASPIRIN_2_SRCS)
-
-test_imu.CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
-test_imu.srcs   += $(IMU_ASPIRIN_2_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_ASPIRIN_2_CFLAGS)
+$(TARGET).srcs += $(IMU_ASPIRIN_2_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_mpu6000.makefile b/conf/firmwares/subsystems/shared/imu_mpu6000.makefile
index 6d906a4a742..065636ac7dc 100644
--- a/conf/firmwares/subsystems/shared/imu_mpu6000.makefile
+++ b/conf/firmwares/subsystems/shared/imu_mpu6000.makefile
@@ -36,14 +36,12 @@ IMU_CFLAGS += -DUSE_$(IMU_MPU_SPI_DEV_UPPER)
 IMU_CFLAGS += -DIMU_MPU_SPI_SLAVE_IDX=$(IMU_MPU_SPI_SLAVE_IDX)
 IMU_CFLAGS += -DUSE_$(IMU_MPU_SPI_SLAVE_IDX)
 
-ap.CFLAGS += $(IMU_CFLAGS)
-ap.srcs   += $(IMU_SRCS)
 
-test_imu.CFLAGS += $(IMU_CFLAGS)
-test_imu.srcs   += $(IMU_SRCS)
-
-test_ahrs.CFLAGS += $(IMU_CFLAGS)
-test_ahrs.srcs   += $(IMU_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_CFLAGS)
+$(TARGET).srcs += $(IMU_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_mpu6000_hmc5883.makefile b/conf/firmwares/subsystems/shared/imu_mpu6000_hmc5883.makefile
index bbde01098e1..d902f15fc3f 100644
--- a/conf/firmwares/subsystems/shared/imu_mpu6000_hmc5883.makefile
+++ b/conf/firmwares/subsystems/shared/imu_mpu6000_hmc5883.makefile
@@ -88,11 +88,12 @@ IMU_CFLAGS += -DUSE_$(IMU_MPU_SPI_DEV_UPPER)
 IMU_CFLAGS += -DIMU_MPU_SPI_SLAVE_IDX=$(IMU_MPU_SPI_SLAVE_IDX)
 IMU_CFLAGS += -DUSE_$(IMU_MPU_SPI_SLAVE_IDX)
 
-ap.CFLAGS += $(IMU_CFLAGS)
-ap.srcs   += $(IMU_SRCS)
 
-test_imu.CFLAGS += $(IMU_CFLAGS)
-test_imu.srcs   += $(IMU_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_CFLAGS)
+$(TARGET).srcs += $(IMU_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_mpu9250_i2c.makefile b/conf/firmwares/subsystems/shared/imu_mpu9250_i2c.makefile
index e08d442631c..626d3f9d203 100644
--- a/conf/firmwares/subsystems/shared/imu_mpu9250_i2c.makefile
+++ b/conf/firmwares/subsystems/shared/imu_mpu9250_i2c.makefile
@@ -39,13 +39,11 @@ IMU_MPU9250_CFLAGS += -DIMU_MPU9250_I2C_DEV=$(MPU9250_I2C_DEV_LOWER)
 IMU_MPU9250_CFLAGS += -DUSE_$(MPU9250_I2C_DEV_UPPER)
 
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-
-ap.CFLAGS += $(IMU_MPU9250_CFLAGS)
-ap.srcs   += $(IMU_MPU9250_SRCS)
-
-test_imu.CFLAGS += $(IMU_MPU9250_CFLAGS)
-test_imu.srcs   += $(IMU_MPU9250_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_MPU9250_CFLAGS)
+$(TARGET).srcs += $(IMU_MPU9250_SRCS)
+endif
 
 
 #
diff --git a/conf/firmwares/subsystems/shared/imu_navgo.makefile b/conf/firmwares/subsystems/shared/imu_navgo.makefile
index 3ab4757bfe5..0bd76349aa8 100644
--- a/conf/firmwares/subsystems/shared/imu_navgo.makefile
+++ b/conf/firmwares/subsystems/shared/imu_navgo.makefile
@@ -14,8 +14,11 @@ IMU_NAVGO_SRCS += peripherals/itg3200.c
 IMU_NAVGO_SRCS += peripherals/adxl345_i2c.c
 IMU_NAVGO_SRCS += peripherals/hmc58xx.c
 
-ap.CFLAGS += $(IMU_NAVGO_CFLAGS)
-ap.srcs   += $(IMU_NAVGO_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_NAVGO_CFLAGS)
+$(TARGET).srcs += $(IMU_NAVGO_SRCS)
+endif
 
 #
 # Simulator
diff --git a/conf/firmwares/subsystems/shared/imu_navstik.makefile b/conf/firmwares/subsystems/shared/imu_navstik.makefile
index 861d20646a0..57353895e24 100644
--- a/conf/firmwares/subsystems/shared/imu_navstik.makefile
+++ b/conf/firmwares/subsystems/shared/imu_navstik.makefile
@@ -37,11 +37,12 @@ NAVSTIK_MPU_I2C_DEV_LOWER=$(shell echo $(NAVSTIK_MPU_I2C_DEV) | tr A-Z a-z)
 IMU_CFLAGS  += -DNAVSTIK_MAG_I2C_DEV=$(NAVSTIK_MAG_I2C_DEV_LOWER) -DNAVSTIK_MPU_I2C_DEV=$(NAVSTIK_MPU_I2C_DEV_LOWER)
 IMU_CFLAGS  += -DUSE_$(NAVSTIK_MAG_I2C_DEV_UPPER)=1 -DUSE_$(NAVSTIK_MPU_I2C_DEV_UPPER)=1
 
-ap.CFLAGS += $(IMU_CFLAGS)
-ap.srcs   += $(IMU_SRCS)
 
-test_imu.CFLAGS += $(IMU_CFLAGS)
-test_imu.srcs   += $(IMU_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_CFLAGS)
+$(TARGET).srcs += $(IMU_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_ppzuav.makefile b/conf/firmwares/subsystems/shared/imu_ppzuav.makefile
index 66b69c02e85..7778cd1caf6 100644
--- a/conf/firmwares/subsystems/shared/imu_ppzuav.makefile
+++ b/conf/firmwares/subsystems/shared/imu_ppzuav.makefile
@@ -18,8 +18,9 @@ else ifeq ($(ARCH), lpc21)
 	IMU_PPZUAV_CFLAGS += -DIMU_PPZUAV_I2C_DEV=i2c0
 endif
 
-ap.CFLAGS += $(IMU_PPZUAV_CFLAGS)
-ap.srcs   += $(IMU_PPZUAV_SRCS)
 
-test_imu.CFLAGS += $(IMU_PPZUAV_CFLAGS)
-test_imu.srcs   += $(IMU_PPZUAV_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_PPZUAV_CFLAGS)
+$(TARGET).srcs += $(IMU_PPZUAV_SRCS)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_px4fmu_v1.7.makefile b/conf/firmwares/subsystems/shared/imu_px4fmu_v1.7.makefile
index 61e3811eb80..0b7cfc4684f 100644
--- a/conf/firmwares/subsystems/shared/imu_px4fmu_v1.7.makefile
+++ b/conf/firmwares/subsystems/shared/imu_px4fmu_v1.7.makefile
@@ -57,13 +57,11 @@ IMU_PX4FMU_SRCS   += peripherals/hmc58xx.c
 IMU_PX4FMU_CFLAGS += -DUSE_I2C2
 
 
-# Keep CFLAGS/Srcs for imu in separate expression so we can assign it to other targets
-
-ap.CFLAGS += $(IMU_PX4FMU_CFLAGS)
-ap.srcs   += $(IMU_PX4FMU_SRCS)
-
-test_imu.CFLAGS += $(IMU_PX4FMU_CFLAGS)
-test_imu.srcs   += $(IMU_PX4FMU_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_PX4FMU_CFLAGS)
+$(TARGET).srcs += $(IMU_PX4FMU_SRCS)
+endif
 
 #
 # NPS simulator
diff --git a/conf/firmwares/subsystems/shared/imu_um6.makefile b/conf/firmwares/subsystems/shared/imu_um6.makefile
index a5e9eb416e8..fdbd8e0ad79 100644
--- a/conf/firmwares/subsystems/shared/imu_um6.makefile
+++ b/conf/firmwares/subsystems/shared/imu_um6.makefile
@@ -17,5 +17,8 @@ IMU_UM6_SRCS   += $(SRC_SUBSYSTEMS)/imu/imu_um6.c
 IMU_UM6_CFLAGS += -DUSE_$(UM6_PORT) -D$(UM6_PORT)_BAUD=$(UM6_BAUD)
 IMU_UM6_CFLAGS += -DUM6_LINK=$(UM6_PORT_LOWER)
 
-ap.CFLAGS += $(IMU_UM6_CFLAGS)
-ap.srcs   += $(IMU_UM6_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_UM6_CFLAGS)
+$(TARGET).srcs += $(IMU_UM6_SRCS)
+endif
diff --git a/conf/firmwares/subsystems/shared/imu_umarim.makefile b/conf/firmwares/subsystems/shared/imu_umarim.makefile
index 84a27cc9c3c..5692804a348 100644
--- a/conf/firmwares/subsystems/shared/imu_umarim.makefile
+++ b/conf/firmwares/subsystems/shared/imu_umarim.makefile
@@ -13,8 +13,11 @@ IMU_UMARIM_CFLAGS += -DIMU_UMARIM_I2C_DEV=$(IMU_UMARIM_I2C_DEV)
 IMU_UMARIM_SRCS += peripherals/itg3200.c
 IMU_UMARIM_SRCS += peripherals/adxl345_i2c.c
 
-ap.CFLAGS += $(IMU_UMARIM_CFLAGS)
-ap.srcs   += $(IMU_UMARIM_SRCS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(IMU_UMARIM_CFLAGS)
+$(TARGET).srcs += $(IMU_UMARIM_SRCS)
+endif
 
 #
 # Simulator
diff --git a/conf/firmwares/subsystems/shared/imu_yai.makefile b/conf/firmwares/subsystems/shared/imu_yai.makefile
index 1aec6d66a3a..1fc8004cacd 100644
--- a/conf/firmwares/subsystems/shared/imu_yai.makefile
+++ b/conf/firmwares/subsystems/shared/imu_yai.makefile
@@ -34,8 +34,8 @@ include $(CFG_SHARED)/imu_b2_common.makefile
 
 # No Magnetometer
 
-ap.srcs += $(imu_srcs)
-ap.CFLAGS += $(imu_CFLAGS)
-
-test_imu.srcs += $(imu_srcs)
-test_imu.CFLAGS += $(imu_CFLAGS)
+# add it for all targets except sim, fbw and nps
+ifeq (,$(findstring $(TARGET),sim fbw nps))
+$(TARGET).CFLAGS += $(imu_CFLAGS)
+$(TARGET).srcs += $(imu_SRCS)
+endif