# Cannot enable UART on Beaglebone **URL:** \ **Category:** Product support\ **Tags:** beaglebone\ **Created:** [October 17, 2018, 11:40pm UTC](https://forums.balena.io/t/cannot-enable-uart-on-beaglebone/4162 "2018-10-17T23:40:04Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![freako987](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/freako987/32/1027_2.png) [@freako987](https://forums.balena.io/u/freako987)\ **Post date:** [October 17, 2018, 11:40pm UTC](https://forums.balena.io/t/cannot-enable-uart-on-beaglebone/4162/1 "2018-10-17T23:40:04Z")
Hi, I’m trying to get the IO ports working on a BeagleBone running the latest resinOS (2.15.1+rev1). I’m trying to use the [Bonescript](https://github.com/jadonk/bonescript) library in a NodeJS runtime on the resin/beaglebone-black-node:8 base image. I want to enable and use UART4, which does not work out of the box. I need to enable it with some command in my Dockerfile/starter script. I tried to follow the solution listed [here](https://forums.balena.io/t/serial-port-on-beaglebone/926) but am encountering errors. Whenever I run `echo BB-UART4 > slots`, a ton of journal errors are spit out at me. Relevant ones are below: ```auto root@14f4739:/sys/devices/platform/bone_capemgr# echo BB-UART4 > slots Broadcast message from systemd-journald@14f4739 (Wed 2018-10-17 23:21:59 UTC): kernel[544]: [463.501752] Internal error: Oops: 17 [#1] PREEMPT SMP ARM Broadcast message from systemd-journald@14f4739 (Wed 2018-10-17 23:21:59 UTC): kernel[544]: [463.606348] Process bash (pid: 1425, stack limit = 0xd182e218) ``` When I inspect dmesg to see what happened, I see the following error(s): ```auto [463.415231] bone_capemgr bone_capemgr: part_number 'BB-UART4', version 'N/A' [463.434656] bone_capemgr bone_capemgr: slot #4: override [463.444639] bone_capemgr bone_capemgr: Using override eeprom data at slot 4 [463.458779] bone_capemgr bone_capemgr: slot #4: 'Override Board Name,00A0,Override Manuf,BB-UART4' [463.475911] Unable to handle kernel NULL pointer dereference at virtual address 0000000c [463.485388] pgd = da670000 [463.492973] [0000000c] *pgd=9a561831, *pte=00000000, *ppte=00000000 [463.501752] Internal error: Oops: 17 [#1] PREEMPT SMP ARM ``` This is in contrast to what should be in dmesg based on the post linked above. So, I am stuck. This would seem to be an incompatibility with the kernel itself. Any help is greatly appreciated! ---
**Author:** ![xginn8](https://avatars.discourse-cdn.com/v4/letter/x/8baadc/32.png) [@xginn8](https://forums.balena.io/u/xginn8)\ **Post date:** [November 8, 2018, 10:04pm UTC](https://forums.balena.io/t/cannot-enable-uart-on-beaglebone/4162/4 "2018-11-08T22:04:42Z")
Hi @freako987! It appears as though `capemgr` is in the process of deprecation [upstream in the Beaglebone linux fork](https://github.com/beagleboard/linux/issues/165), in favor of `u-boot`. We are tracking the fix for that [here](https://github.com/balena-os/resin-beaglebone/issues/156), and will let you know when it is merged. Hope this helps! ---
**Author:** ![sradevski](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/sradevski/32/1609_2.png) [@sradevski](https://forums.balena.io/u/sradevski)\ **Post date:** [March 4, 2019, 5:12pm UTC](https://forums.balena.io/t/cannot-enable-uart-on-beaglebone/4162/12 "2019-03-04T17:12:53Z")
Hi there, Just to update you that the issue has been fixed in BalenaOS v2.29.2+rev1 and above. Let us know in case you are still facing the same issue. Regards, Steve ---
**Author:** ![sradevski](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/sradevski/32/1609_2.png) [@sradevski](https://forums.balena.io/u/sradevski)\ **Post date:** [March 4, 2019, 5:13pm UTC](https://forums.balena.io/t/cannot-enable-uart-on-beaglebone/4162/13 "2019-03-04T17:13:01Z")
Hi there, Just to update you that the issue has been fixed in BalenaOS v2.29.2+rev3 and above. Let us know in case you are still facing the same issue. Regards, Steve