Cannot enable UART5 with Beaglebone black kernel 4.9.82-ti-r102

I am trying to set pins P8.37 and P8.38 to UART mode as follow:

debian@beaglebone:~$ config-pin P8.38 uart

P8_38 pinmux file not found!

sudo: no askpass program specified, try setting SUDO_ASKPASS

Cannot write pinmux file: /sys/devices/platform/ocp/ocp*P8_38_pinmux/state

debian@beaglebone:~$ config-pin P8.37 uart

P8_37 pinmux file not found!

sudo: no askpass program specified, try setting SUDO_ASKPASS

Cannot write pinmux file: /sys/devices/platform/ocp/ocp*P8_37_pinmux/state

It seems that config-pin function is looking in the wrong directory for P8_37 and P8_38 as the pin mux file is located at “/sys/devices/platform/ocp/of_node” and not at “ls /sys/devices/platform/ocp/”. The following prove my statement:

$ ls /sys/devices/platform/ocp/of_node

#address-cells mcasp@4803C000 P8_24_pinmux P9_15_pinmux serial@44e09000

aes@53500000 mmc@47810000 P8_25_pinmux P9_16_pinmux serial@48022000

can@481cc000 mmc@48060000 P8_26_pinmux P9_17_pinmux serial@48024000

can@481d0000 mmc@481d8000 P8_27_pinmux P9_18_pinmux serial@481a6000

cape-universal name P8_28_pinmux P9_19_pinmux serial@481a8000

compatible ocmcram@40300000 P8_29_pinmux P9_20_pinmux serial@481aa000

edma@49000000 P8_03_pinmux P8_30_pinmux P9_21_pinmux sgx@56000000

elm@48080000 P8_04_pinmux P8_31_pinmux P9_22_pinmux sham@53100000

emif@4c000000 P8_05_pinmux P8_32_pinmux P9_23_pinmux #size-cells

epwmss@48300000 P8_06_pinmux P8_33_pinmux P9_24_pinmux spi@48030000

epwmss@48302000 P8_07_pinmux P8_34_pinmux P9_25_pinmux spi@481a0000

epwmss@48304000 P8_08_pinmux P8_35_pinmux P9_26_pinmux spinlock@480ca000

ethernet@4a100000 P8_09_pinmux P8_36_pinmux P9_27_pinmux ti,hwmods

gpio@44e07000 P8_10_pinmux P8_37_pinmux P9_28_pinmux timer@44e31000

gpio@4804c000 P8_11_pinmux P8_38_pinmux P9_29_pinmux timer@48040000

gpio@481ac000 P8_12_pinmux P8_39_pinmux P9_30_pinmux timer@48042000

gpio@481ae000 P8_13_pinmux P8_40_pinmux P9_31_pinmux timer@48044000

gpmc@50000000 P8_14_pinmux P8_41_pinmux P9_41_pinmux timer@48046000

i2c@44e0b000 P8_15_pinmux P8_42_pinmux P9_42_pinmux timer@48048000

i2c@4802a000 P8_16_pinmux P8_43_pinmux P9_91_pinmux timer@4804a000

i2c@4819c000 P8_17_pinmux P8_44_pinmux P9_92_pinmux tptc@49800000

interrupt-controller@48200000 P8_18_pinmux P8_45_pinmux phandle tptc@49900000

l4_wkup@44c00000 P8_19_pinmux P8_46_pinmux pruss@4a300000 tptc@49a00000

lcdc@4830e000 P8_20_pinmux P9_11_pinmux pruss_soc_bus@4a326000 tscadc@44e0d000

linux,phandle P8_21_pinmux P9_12_pinmux ranges usb@47400000

mailbox@480C8000 P8_22_pinmux P9_13_pinmux rng@48310000 wdt@44e35000

mcasp@48038000 P8_23_pinmux P9_14_pinmux rtc@44e3e000

Further, this are info of my system and setup:

Image I used: Debian 9.3 2018-03-05 4GB SD IoT

debian@beaglebone:~$ cat /boot/uEnv.txt





###U-Boot Overlays###


###Master Enable