README.md

BBBLUE-MPU9250-00A0.dts goes in /opt/source/bb.org-overlays/src/arm

cd /opt/source/bb.org-overlays
make
sudo make install

uEnv.txt goes in /boot and must be written as root!

BBBLUE-MPU9250-00A0.dts

/*
 * Copyright (C) 2012,2019 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

/dts-v1/;
/plugin/;

#include <dt-bindings/interrupt-controller/irq.h>

/ {
	compatible = "ti,am335x-bone-blue", "ti,beaglebone", "ti,beaglebone-black";

	/* identification */
	part-number = "BBBLUE-MPU9250";
	version = "00A0";

	/*
	 * Free up the pins used by the cape from the pinmux helpers.
	 */
	fragment@0 {
		target = <&i2c2>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;

			mpu9250@68 {
				compatible = "invensense,mpu9250";
				reg = <0x68>;
				interrupt-parent = <&gpio3>;
				interrupts = <21 IRQ_TYPE_LEVEL_HIGH>;
				i2c-gate {
					#address-cells = <1>;
					#size-cells = <0>;
					ax8975@c {
						compatible = "asahi-kasei,ak8975";
						reg = <0x0c>;
					};
				};
			};
		};
	};
};

uEnv.txt

#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0

uname_r=4.19.50-ti-r20
#uuid=
#dtb=

###U-Boot Overlays###
###Documentation: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays
###Master Enable
enable_uboot_overlays=1
###
###Overide capes with eeprom
#uboot_overlay_addr0=/lib/firmware/<file0>.dtbo
#uboot_overlay_addr1=/lib/firmware/<file1>.dtbo
#uboot_overlay_addr2=/lib/firmware/<file2>.dtbo
#uboot_overlay_addr3=/lib/firmware/<file3>.dtbo
###
###Additional custom capes
#uboot_overlay_addr4=/lib/firmware/BBBLUE-UDA1334-00A0.dtbo
uboot_overlay_addr5=/lib/firmware/BBBLUE-MPU9250-00A0.dtbo
#uboot_overlay_addr6=/lib/firmware/<file6>.dtbo
#uboot_overlay_addr7=/lib/firmware/<file7>.dtbo
###
###Custom Cape
#dtb_overlay=/lib/firmware/<file8>.dtbo
###
###Disable auto loading of virtual capes (emmc/video/wireless/adc)
#disable_uboot_overlay_emmc=1
#disable_uboot_overlay_video=1
#disable_uboot_overlay_audio=1
#disable_uboot_overlay_wireless=1
#disable_uboot_overlay_adc=1
###
###PRUSS OPTIONS
###pru_rproc (4.4.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-4-TI-00A0.dtbo
###pru_rproc (4.14.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo
###pru_rproc (4.19.x-ti kernel)
uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-19-TI-00A0.dtbo
###pru_uio (4.4.x-ti, 4.14.x-ti, 4.19.x-ti & mainline/bone kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-UIO-00A0.dtbo
###
###Cape Universal Enable
enable_uboot_cape_universal=1
###
###Debug: disable uboot autoload of Cape
#disable_uboot_overlay_addr0=1
#disable_uboot_overlay_addr1=1
#disable_uboot_overlay_addr2=1
#disable_uboot_overlay_addr3=1
###
###U-Boot fdt tweaks... (60000 = 384KB)
#uboot_fdt_buffer=0x60000
###U-Boot Overlays###

cmdline=coherent_pool=1M net.ifnames=0 rng_core.default_quality=100 cape_universal=enable quiet

#In the event of edid real failures, uncomment this next line:
#cmdline=coherent_pool=1M net.ifnames=0 rng_core.default_quality=100 cape_universal=enable quiet video=HDMI-A-1:1024x768@60e

#Use an overlayfs on top of a read-only root filesystem:
#cmdline=coherent_pool=1M net.ifnames=0 rng_core.default_quality=100 cape_universal=enable quiet overlayroot=tmpfs

##enable Generic eMMC Flasher:
#cmdline=init=/opt/scripts/tools/eMMC/init-eMMC-flasher-v3.sh