ok. now please find below the uEnv.txt directly from /boot (not from rootfs…)! but it don’t work although
#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_3.0
uname_r=4.1.15-ti-rt-r43
#uuid=
#dtb=
##BeagleBone Black/Green dtb’s for v4.1.x (BeagleBone White just works…)
##BeagleBone Black: HDMI (Audio/Video) disabled:
#dtb=am335x-boneblack-emmc-overlay.dtb
##BeagleBone Black: eMMC disabled:
#dtb=am335x-boneblack-hdmi-overlay.dtb
##BeagleBone Black: HDMI Audio/eMMC disabled:
#dtb=am335x-boneblack-nhdmi-overlay.dtb
##BeagleBone Black: HDMI (Audio/Video)/eMMC disabled:
#dtb=am335x-boneblack-overlay.dtb
##BeagleBone Black: wl1835
#dtb=am335x-boneblack-wl1835mod.dtb
##BeagleBone Green: eMMC disabled
#dtb=am335x-bonegreen-overlay.dtb
cmdline=coherent_pool=1M quiet cape_universal=enable
#In the event of edid real failures, uncomment this next line:
cmdline=coherent_pool=1M quiet cape_universal=enable video=HDMI-A-1:x800@400e
##Example v3.8.x
#cape_disable=capemgr.disable_partno=
#cape_enable=capemgr.enable_partno=
##Example v4.1.x
#cape_disable=bone_capemgr.disable_partno=
#cape_enable=bone_capemgr.enable_partno=
##Disable HDMI/eMMC (v3.8.x)
#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN,BB-BONE-EMMC-2G
##Disable HDMI (v3.8.x)
#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN
##Disable eMMC (v3.8.x)
#cape_disable=capemgr.disable_partno=BB-BONE-EMMC-2G
##Audio Cape (needs HDMI Audio disabled) (v3.8.x)
#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI
#cape_enable=capemgr.enable_partno=BB-BONE-AUDI-02
##enable Generic eMMC Flasher: