mathiashro:

Device:
UBNT-ERX

Version:
DISTRIB_REVISION='r2993+792-b9a408c2b4'
DISTRIB_CODENAME='reboot'

During Boot:
Fri Dec 15 18:35:25 2017 daemon.debug zram_start: activating '/dev/zram0' for swapping (124 MegaBytes)
Fri Dec 15 18:35:25 2017 daemon.notice procd: /etc/rc.d/S15zram: zram_start: activating '/dev/zram0' for swapping (124 MegaBytes)
Fri Dec 15 18:35:25 2017 daemon.debug zram_reset: enforcing defaults via /sys/block/zram0/reset
Fri Dec 15 18:35:25 2017 daemon.notice procd: /etc/rc.d/S15zram: zram_reset: enforcing defaults via /sys/block/zram0/reset
Fri Dec 15 18:35:25 2017 kern.info kernel: [ 21.187248] zram0: detected capacity change from 0 to 130023424
Fri Dec 15 18:35:25 2017 daemon.notice procd: /etc/rc.d/S15zram: Setting up swapspace version 1, size = 130019328 bytes
Fri Dec 15 18:35:25 2017 kern.info kernel: [ 21.207813] Adding 126972k swap on /dev/zram0. Priority:-1 extents:1 across:126972k SS
Fri Dec 15 18:35:25 2017 daemon.crit zram_applicable: [ERROR] device '/dev/zram1' not found
Fri Dec 15 18:35:25 2017 daemon.notice procd: /etc/rc.d/S15zram: zram_applicable: [ERROR] device '/dev/zram1' not found

Seems like for each CPU a "dedicated" zram is been tried to mounted which is failing. ER-X does have a Dual Core CPU.

If you need more information, please let me know.