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Warning: This manual is moved to https://help.mikrotik.com/docs/display/SWOS/SwOS


SwOS is an operating system designed specifically for administration of MikroTik switch products.

SwOS is configurable from your web browser. It gives you all the basic functionality for a managed switch, plus more: allows to manage port-to-port forwarding, broadcast storm control, apply MAC filter, configure VLANs, mirror traffic, apply bandwidth limitation and even adjust some MAC and IP header fields.


Warning: Each RouterBoard switch series device has its own firmware which cannot be installed on other series models!

  • CRS326-24G-2S+ supports SwOS v2.0 and newer.
  • CRS317-1G-16S+ supports SwOS v2.3 and newer.
  • CRS328-24P-4S+ supports SwOS v2.7 and newer.
  • CRS328-4C-20S-4S+ supports SwOS v2.7 and newer.
  • CRS305-1G-4S+ supports SwOS v2.8 and newer.
  • CRS309-1G-8S+ supports SwOS v2.8 and newer.
  • CRS312-4C+8XG supports SwOS v2.10 and newer.
  • CRS326-24S+2Q+ supports SwOS v2.10 and newer.
  • CRS318-16P-2S+ supports SwOS v2.11 and newer.
  • CRS318-1Fi-15Fr-2S supports SwOS v2.11 and newer.
  • CRS354-48G-4S+2Q+ supports SwOS v2.13 and newer.
  • CRS354-48P-4S+2Q+ supports SwOS v2.13 and newer.

CRS3xx series features

  • Full non-blocking wirespeed switching
  • Up to 16k MAC entries in Host table
  • Forwarding Database works based on SVL or IVL
  • Port Isolation
  • Jumbo frame support - 10218 bytes
Spanning Tree Protocol
  • RSTP support
Link Aggregation
  • Supports 802.3ad LACP groups
  • Supports static link aggregation groups
  • Up to 16 link aggregation groups
  • Up to 8 member ports per a group
  • Hardware automatic failover and load balancing
Multicast Forwarding
  • IGMP Snooping support
  • Unknown Multicast Filtering
  • Port based mirroring
  • Fully compatible with IEEE802.1Q
  • Port based VLAN
  • Up to 250 VLAN entries (limited by SwOS)
  • VLAN filtering
  • Port Lock
  • Broadcast Storm Control
  • DHCP & PPPoE Snooping
Quality of Service (QoS)
  • Ingress traffic limiting
Access Control List
  • Ingress ACL tables
  • Up to 32 ACL rules (limited by SwOS)
  • Classification based on ports, L2, L3, L4 protocol header fields
  • ACL actions include filtering, forwarding and modifying of the protocol header fields


This table clarifies the main differences between Cloud Router Switch models.

Model Switch Chip Serial console PoE-in support PoE-out support Health monitor
CRS326-24G-2S+ Marvell-98DX3236 + ether1, Passive PoE - CPU temperature
CRS328-24P-4S+ Marvell-98DX3236 + - ether1 - ether24, 802.3af/at CPU and board temperature, fan speed, PSU voltage and current, PoE-out monitoring
CRS328-4C-20S-4S+ Marvell-98DX3236 + - - CPU temperature, fan speed, PSU state
CRS317-1G-16S+ Marvell-98DX8216 + - - CPU temperature, fan speed, PSU state
CRS305-1G-4S+ Marvell-98DX3236 - ether1, 802.3af/at - CPU temperature
CRS309-1G-8S+ Marvell-98DX8208 + ether1, 802.3af/at - CPU temperature
CRS312-4C+8XG Marvell-98DX8212 + - - CPU temperature, fan speed, PSU state
CRS326-24S+2Q+ Marvell-98DX8332 + - - CPU temperature, fan speed, PSU state
CRS318-16P-2S+ Marvell-98DX226S - - ether1 - ether16, 802.3af/at CPU temperature, PSU voltage and current, PoE-out monitoring.
CRS318-1Fi-15Fr-2S Marvell-98DX224S - ether1-ether14, ether16, Passive PoE ether15, Passive PoE CPU temperature
CRS354-48G-4S+2Q+ Marvell-98DX3257 + - - CPU and board temperature, fan speed, PSU voltage and current
CRS354-48P-4S+2Q+ Marvell-98DX3257 + - ether1 - ether48, 802.3af/at CPU and board temperature, fan speed, PSU voltage and current, PoE-out monitoring

Connecting to the Switch

Open your web browser and enter IP address of your Switch ( by default) and login screen will appear.

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SwOS Login

SwOS default IP address:, user name: admin and there is no password.


Note: MikroTik Neighbor Discovery protocol tools can be used to discover IP address of Mikrotik switch. Manual:IP/Neighbor_discovery. Currently LLDP is not supported.

Interface Overview

SwOS interface menu consists of multiple tabs depending on the device model. These are all possible SwOS menus: Link, PoE, SFP, Port Isolation, LAG, Forwarding, RSTP, Stats, Errors, Hist, VLAN, VLANs, Hosts, IGMP, SNMP, ACL, System, Health and Upgrade.

Description of buttons in SwOS configuration tool:

  • Append - add new item to the end of the list
  • Apply All - applies current configuration changes
  • Cut - removes item from the list
  • Clear - resets properties of the item
  • Discard Changes - removes unsaved configuration
  • Insert - add new item to the list (places it before current item)
  • Sort - sort VLAN table by VLAN-IDs; sort host table by MAC addresses

  • Change Password - changes password of the switch
  • Logout - logout from current Switch
  • Reboot - reboot the switch
  • Reset Configuration - reset configuration back to factory defaults
  • Choose File - browse for upgrade or backup file
  • Upgrade - upgrade firmware of the Switch
  • Restore Backup - restore Switch using selected backup file
  • Save Backup - generate and download backup file from the Switch


System Tab performs the following functions:

  • General information about Switch
  • Switch management
  • Configuration reset
  • Backup and restore configuration


Note: SwOS uses a simple algorithm to ensure TCP/IP communication - it just replies to the same IP and MAC address packet came from. This way there is no need for Default Gateway on the device itself.

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General Settings

Property Description
Address AcquisitionSpecify which address acquisition method to use:
  • DHCP with fallback - For first 10 seconds switch uses DHCP client. If request is unsuccessful, then address is set as a Static IP Address value
  • static - Address is set as a Static IP Address value
  • DHCP only - Switch uses DHCP client to acquire address
Static IP AddressIP address of the switch in case of Address Acquisition is set as DHCP with fallback or static
IdentityName of the switch (for Mikrotik Neighbor Discovery protocol)
Allow FromIP address from which the switch is accessible. Default value is '' - any address
Allow From PortsList of switch ports from which it is accessible
Allow From VLANVLAN ID from which the switch is accessible (VLAN Mode on ingress port must be other than disabled in order to connect)
WatchdogEnable or disable system Watchdog. It will reset CPU of the switch in case of fault condition
Independent VLAN LookupEnable or disable independent VLAN lookup in the Host table for packet forwarding
IGMP SnoopingEnable or disable IGMP Snooping
IGMP Fast LeaveEnables or disables IGMP fast leave feature on the switch port. This property only has an effect when IGMP Snooping is enabled.
Mikrotik Discovery ProtocolEnable or disable Mikrotik Neighbor Discovery protocol
MAC AddressMAC address of the switch (Read-only)
Serial NumberSerial number of the switch (Read-only)
Board NameMikroTik model name of the switch (Read-only)
UptimeCurrent switch uptime (Read-only)

DHCP & PPPoE Snooping

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DHCP & PPPoE snooping settings

Property Description
Trusted PortsGroup of ports, which allows DHCP or PPPoE servers to provide a requested information. Mainly used to limit unauthorized servers to provide malicious information for users, access ports usually do not configure as trusted
Add Information OptionEnables or disables DHCP Option-82 information. When enabled, the Option-82 information (Agent Remote ID and Circuit ID) is added for DHCP packets received from untrusted ports. Can be used together with Option-82 capable DHCP server to assign IP addresses and implement policies

Password and Backup

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System Management Settings


Link Tab allows you to configure each interface settings and monitor link status

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Link Settings

Property Description
EnabledEnable or disable port
NameEditable port name
Link StatusCurrent link status (Read-only)
Auto NegotiationEnable or disable auto negotiation
SpeedSpecify speed setting of the port (requires auto negotiation to be disabled)
Full DuplexSpecify duplex mode of the port (requires auto negotiation to be disabled)
Flow control Tx/RxEnable or disable 802.3x Flow control


Devices with PoE-out support have some configuration options and certain monitoring features, like PoE-out current, voltage, etc. For more detailed description, see Manual:PoE-Out.

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PoE tab


SFP tab allows you to monitor status of SFP/SFP+ modules.

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Port Isolation

Port Isolation table allows or restricts traffic forwarding between specific ports. By default, all available switch chip ports can communicate with any other port, there is no isolation used. When the checkbox is enabled/ticked you allow to forward traffic from this port towards the ticked port. Below are some port isolation examples.

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In some scenarios you might need to isolate a group of devices from other groups. In this example devices on Port1-Port5 are not able to communicate with Port6-Port10 devices, and vice versa.
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In some scenarios you might need to forward all traffic to an uplink port while all other ports are isolated from each other. This kind of setup is called Private VLAN configuration. The switch will forward all Ethernet frames only to the uplink Port1, while uplink can reach all other ports
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Individual isolated Port1 (e.g. for management purpose), it cannot send or receive traffic from any other port

Note: It is possible to check/uncheck multiple checkboxes by checking one of them and then dragging horizontally (Click & Drag).


Note: (R)STP will only work properly in Private VLAN setups. In setups with multiple isolated switch groups (R)STP might not properly receive BPDUs and therefore fail to detect network loops.


IEEE 802.3ad (LACP) compatible link aggregation is supported, as well as static link aggregation to ensure failover and load balancing based on Layer2, Layer3 and Layer4 hashing.

Up to 16 link aggregation groups with up to 8 ports per a group are supported.

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Each individual port can be configured as Passive LACP, Active LACP or a Static LAG port.

Property Description
Mode (default: passive) Specify LACP packet exchange mode or Static LAG mode on ports:
  • Passive: Place port in listening state, use LACP only when it's contrary port uses active LACP mode
  • Active: Prefer to start LACP regardless contrary port mode
  • Static: Set port in a Static LAG mode
Property Description
GroupSpecify a Static LAG group
Trunk (read only)Represents group number port belongs to.
Partner (read only)Represents partner mac-address.


Forwarding Tab provides advanced forwarding options among switch ports, port locking, port mirroring, bandwidth limit and broadcast storm control features.

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Forwarding Settings

Property Description
Port Lock
  • Port Lock - Enables or disables MAC address learning on this port. When option is enabled, it will restrict MAC address learning and static MAC addresses should be configured. Any received frames with unknown source MAC address will be dropped
  • Lock On First - Allows to learn source MAC address from the first received frame, this property should be used together with Port Lock. Learning of the first MAC address will reset every time an interface status changes
Port Mirroring
  • Mirror Ingress - Whether traffic entering this port must be copied and forwarded to mirroring target port
  • Mirror Egress - Whether traffic leaving this port must be copied and forwarded to mirroring target port
  • Mirror To - Mirroring target port
Broadcast Storm Control
  • Storm Rate (%) - Limit the number of broadcast packets transmitted by an interface. The rate is measured in percents of the link speed.
  • Include Unknown Unicast - Include unicast packets without an entry in host table in Storm Rate limitation
Multicast Flood Control
  • Flood Unknown Multicast - Changes the multicast flood option on switch port, only controls the egress traffic. When enabled, the bridge allows flooding multicast packets to the specified switch port, but when disabled, it restricts multicast traffic from being flooded. The setting affects all multicast traffic, this includes non-IP, IPv4, IPv6 and the link-local multicast ranges (e.g. and ff02::1).
Bandwidth Limit
  • Ingress Rate - Limit traffic entering this port (bps)

Note: It is possible to limit ingress traffic per port basis with traffic policer. The ingress policer controls the received traffic with packet drops. Everything that exceeds the defined limit will get dropped. This can affect the TCP congestion control mechanism on end hosts and achieved bandwidth can be actually less than defined.


Per port and global RSTP configuration and monitoring is available in the RSTP menu.

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RSTP Settings

Property Description
Bridge Priority (hex)RSTP bridge priority for Root Bridge selection
Port Cost ModeThere are two methods for automatically detecting RSTP port cost depending on link speed.
  • short: 40G - 1; 10G - 2; 1G - 4; 100M - 10; 10M - 100
  • long: 40G - 500; 10G - 2000; 1G - 20000; 100M - 200000; 10M - 2000000
Root BridgeThe priority and MAC address of the selected Root Bridge in the network (Read-only)
Property Description
RSTPEnable or disable STP/RSTP functionality on this port
Mode Shows STP/RSTP functionality mode on specific port (Read-only):
  • RSTP
  • STP
RoleShows specific port role (Read-only):
  • root - port that is facing towards the root bridge and will be used to forward traffic from/to the root bridge
  • alternate - port that is facing towards root bridge, but is not going to forward traffic (a backup for root port)
  • backup - port that is facing away from the root bridge, but is not going to forward traffic (a backup for non-root port)
  • designated - port that is facing away from the root bridge and is going to forward traffic
  • disabled - port that is not strictly part of STP (RSTP functionality is disabled)
Root Path CostShows root path cost for ports that are facing root bridge (Read-only)
  • edge - ports that are not supposed to receive any BPDUs, should be connected to end station (Read-only)
  • point-to-point - ports that operates in full-duplex links, can be part of STP and operate in forwarding state (Read-only)
StateShows each port state (Read-only):
  • forwarding - port participates in traffic forwarding and is learning MAC addresses, is receiving BPDUs
  • discarding - port does not participate in traffic forwarding and is not learning MAC addresses, is receiving BPDU
  • learning - port does not participate in traffic forwarding, but is learning MAC addresses

Stats, Errors and Histogram

These menus provide detailed information about received and transmitted packets.

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Port statistics
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Port error statistics
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Port histogram statistics

Note: Statistics for SFP+ interface are cleared whenever an active SFP+ link is established.


VLAN configuration for switch ports.

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Port VLAN Settings

Property Description
VLAN Mode (disabled | optional | enabled | strict; Default: optional) VLAN filtering mode, these options are relevant to egress ports (except for strict mode).
  • disabled - VLAN table is not used. Switch discards packets with a VLAN tag on egress ports. If the packet has a VLAN tag and the VLAN ID matches Default VLAN ID on egress ports, then with VLAN Receive=any the switch will remove the VLAN tag and forward the packet.
  • optional - Disabled VLAN filtering. Handle packets with VLAN tag ID that is not present in VLAN table just like packets without VLAN tag.
  • enabled - Enabled VLAN filtering. Drop packets with VLAN tag ID that is not present in VLAN table. Default VLAN ID must be specified for access ports since it will be used to tag ingress traffic and untag egress traffic for the certain port.
  • strict - Enabled VLAN filtering with additional ingress filtering, which checks if the ingress port is a member of the received VLAN ID in the VLAN table. Received packets on the ingress port with a VLAN ID that does not match with VLAN table will be dropped. Default VLAN ID must be specified for access ports since it will be used to tag ingress traffic and untag egress traffic for the certain port.
VLAN Receive (any | only tagged | only untagged; Default: optional) Ingress traffic filtering based on VLAN tag presence.
  • any - Allows tagged and untagged packets on a certain port
  • only tagged - Allows only packets with a VLAN tag
  • only untagged - Allows only packets without a VLAN tag
Default VLAN ID (integer: 1..4095; Default: 1) VLAN ID which will be assigned on ingress traffic. Only has effect on untagged traffic, it will be ignored for tagged traffic. This parameter is usually used to allocate access ports with specific VLAN. It is also used to untag egress traffic if packet's VLAN ID matches Default VLAN ID.
Force VLAN ID (integer: yes | no; Default: no) Assigns the Default VLAN ID value to all ingress traffic (tagged and untagged). Has effect in all VLAN Modes. If port receives tagged traffic and Default VLAN ID is set to 1, then with this parameter the egress traffic will be untagged.

VLAN membership configuration for switch ports.

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VLAN Table Settings

Property Description
VLAN ID (integer: 1..4095; Default: 0) VLAN ID to which assign ports.
Name (text; Default: ) Short description of the VLAN.
Port Isolation (yes | no; Default: yes) Use settings from Port Isolation menu to isolate the defined VLAN to only certain ports. When disabled, the switch will ignore port isolation configuration and forward traffic with the defined VLAN ID only to ports that are checked as members.
Learning (yes | no; Default: yes) Enables or disables MAC address learning on the defined VLAN. If disabled, then all learned MAC addresses will appear as they have had been learned from VLAN 1.
Mirror (yes | no; Default: no) Enables or disables VLAN based mirroring. When enabled and Mirror To is set in the Forwarding menu, then all traffic from the defined VLAN will be mirrored to the selected port.
IGMP Snooping (yes | no; Default: no) Enables or disables IGMP Snooping on the defined VLAN. When enabled, the switch will listen to IGMP Join and Leave requests from the defined VLAN and only forward traffic to ports, which have sent IGMP membership requests from the defined VLAN. When disabled, the switch will flood all VLAN member ports with Multicast traffic.
Members (ports; Default: none) Group of ports, which are allowed to forward traffic on the defined VLAN.

VLAN Configuration Example

Simple trunk and access port configuration, as well as trunk and hybrid port configuration examples can be found in this article - SWOS/CSS326-VLAN-Example.


This table represents dynamically learnt MAC address to port mapping entries. It can contain two kinds of entries: dynamic and static. Dynamic entries get added automatically, this is also called a learning process: when switch receives a packet from certain port, it adds the packet's source MAC address and port it received the packet from to host table, so when a packet comes in with certain destination MAC address it knows to which port it should forward the packet. If the destination MAC address is not present in host table then it forwards the packet to all ports in the group. Dynamic entries take about 5 minutes to time out. CRS3xx devices supports 16383 host table entries.

Static entries will take over dynamic if dynamic entry with same mac-address already exists. Also by adding a static entry you get access to some more functionality.

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Host Table

Property Description
PortsPorts the packet should be forwarded to
MACMAC address
DropPacket with certain MAC address coming from certain ports can be dropped
MirrorPacket can be cloned and sent to mirror-target port
Property Description
PortPorts the packet should be forwarded to (Read-only)
MACLearned MAC address (Read-only)
VLAN IDLearned VLAN ID (Read-only)

IGMP Snooping

IGMP Snooping which controls multicast streams and prevents multicast flooding is implemented in SwOS starting from version 2.5. The feature allows a switch to listen in the IGMP conversation between hosts and routers.

Enable this option under System tab.

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IGMP Snooping under System tab

Available IGMP snooping data can be found under IGMP tab:

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IGMP Snooping table

It is possible to enable IGMP Snooping for a specific VLAN ID under VLANs menu.


Note: IGMP Snooping for VLANs requires enabled "Independent VLAN Lookup" in the System menu.

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IGMP Snooping VLANs settings


SwOS supports SNMP v1 and uses IF-MIB, SNMPv2-MIB, BRIDGE-MIB and MIKROTIK-MIB (only for health, PoE-out and SFP diagnostics) for SNMP reporting.

Available SNMP data:

  • System information
  • System uptime
  • Port status
  • Interface statistics
  • Host table information
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SNMP settings

Property Description
EnabledEnable or disable SNMP service
CommunitySNMP community name
Contact InfoContact information for the NMS
LocationLocation information for the NMS


An access control list (ACL) rule table is very powerful tool allowing wire speed packet filtering, forwarding and VLAN tagging based on L2,L3 protocol header field conditions. Each rule contains a conditions part and an action part.

CSS326-24G-2S+ ACL table

Conditions part parameters

Property Description
FromPort that packet came in from
MAC SrcSource MAC address and mask
MAC DstDestination MAC address and mask
EthertypeProtocol encapsulated in the payload of an Ethernet Frame

VLAN header presence:

  • any
  • present
  • not present
PriorityPriority in VLAN tag
IP Src (IP/netmask:port)Source IPv4 address, netmask and L4 port number
IP Dst (IP/netmask:port)Destination IPv4 address, netmask and L4 port number
Protocol (integer)IP protocol

Action part parameters

Property Description
Redirect ToForce new packets destination port
MirrorClones packet and sends it to mirror-target port
RateLimits bandwidth (bps)
DropDrop packet
Set VLAN IDChanges the VLAN tag ID, if VLAN tag is present
PriorityChanges the VLAN tag priority bits, if VLAN tag is present


This menu provides different health related properties.

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CRS328-24P-4S+ Health

Property Description
CPU TemperatureShows CPU temperature in celsius temperature scale (Read-only)
Board TemperatureShows PCB temperature in celsius temperature scale (Read-only)
FANShows FAN rotational speed (Read-only)
PSUShows PSU related information depending on device model (Read-only):
  • PSU state, either failed or ok (for CRS328-20S-4C-4S+, CRS317-1G-16S+, CRS312-4C+8XG, CRS326-24S+2Q+)
  • PSU voltage and consumed miliamperes by PoE-out connected devices (CRS328-24P-4S+, CRS318-16P-2S+)

Note: For devices with only a CPU temperature sensor (CRS326-24G-2S+, CRS305-1G-4S+, CRS309-1G-8S+, CRS318-1Fi-15Fr-2S) health information is available under System menu.

Dual Boot

“Dual Boot” feature allows you to choose which operating system you prefer to use, RouterOS or SwOS. Boot RouterOS option is under System tab:

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Boot RouterOS option

Alternative Dual Boot possibilities: Dual Boot manual

Configuring SwOS using RouterOS

Since RouterOS 6.43 it is possible to load, save and reset SwOS configuration, as well as upgrade SwOS and set an IP address for the switch by using RouterOS. For more details see this article - Configuring SwOS using RouterOS

Reset and Reinstall

With a reset button you can restore RouterOS default-configuration, from where you can configure SwOS using RouterOS.

CRS3xx devices with a serial console have some additional options.

  • To change between RouterOS and SwOS follow these steps:
  1. Connect to the device using a serial console
  2. Enter RouterBOOT setup
  3. Chose "j - boot os"
  4. Chose either RouterOS or SwOS
  • It is possible to load a SwOS backup firmware in case standard firmware breaks or upgrade fails:
  1. Connect to the device using a serial console
  2. Boot SwOS
  3. Choose "p - boot primary SwOS"
  4. After loading backup firmware, it is possible to connect to using a web browser and install new SwOS firmware.
  • To reset SwOS configuration:
  1. Connect to the device using a serial console
  2. Boot SwOS
  3. Choose "r - reset configuration"
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Dual boot
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SwOS serial console access