# Applicable for RouterOS above 6.45.1
# see https://wiki.mikrotik.com/wiki/Dual_SIM_Application#Initial_settings

:log "info" "SIM toggled by the script"

:local simSlot [/system routerboard modem get sim-slot]

:if ( $simSlot = "a" ) do={
  /system routerboard modem set sim-slot=b
} else={
  /system routerboard modem set sim-slot=a
}