CPU	Ram	Flash	Network	USB	Serial	JTag	MiniPCI
Atheros AR7161 680/800 MHz	256MiB	128MiB, 1x Micro-SD-socket	9x 1000Base-T	1x 2.0 unpowered	Yes (console)	??? (contacts on PCB)	3x Type IIIA/B

Shop	Country	Routerboard 493G	Encasing CA493	Last checked
http://shop.meconet.de/	DE	140,- €	19,- €	2012-12-25
http://varia-store.com/	DE	172,- €	20,- €	2012-12-25
http://varia-store.com/	DE	220,- $	26,- $	2012-12-25

Please check out the article Flash Layout. It contains an example and a couple of explanations.

root@OpenWrt:/# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 0000b000 00001000 "routerboot"
mtd1: 00001000 00001000 "hard_config"
mtd2: 00002000 00001000 "bios"
mtd3: 00001000 00001000 "soft_config"
mtd4: 00040000 00020000 "booter"
mtd5: 003c0000 00020000 "kernel"
mtd6: 07c00000 00020000 "rootfs"

The two partitions used to install OpenWrt are kernel and rootfs. Their sizes are in bytes with hex, which translates to 3840KiB for kernel and 126976KiB for rootfs.

The bootloader is able to load an image in ELF-format via BOOTP/DHCP and TFTP into RAM and execute it.

This is the easiest way to achieve a live boot of your RB493G, but it requires that you already have an OpenWrt router with net-access available. You will need to obtain an elf-image for the RB493G, and make it available to the other router. If you have enough memory available on the other router, you can put the image on the /tmp folder there, e.g., like this:

ssh root@192.168.1.1
wget --directory-prefix=/tmp http://downloads.openwrt.org/attitude_adjustment/12.09-beta2/ar71xx/nand/openwrt-ar71xx-nand-vmlinux-initramfs.elf

Now enable dnsmasq's built in tftp server, and point it to the correct locations, e.g., like this: That's it, Save and apply, connect the Eth1/WAN port of RB493G to one of the other routers LAN ports, and continue to Setup the Routerboard.

You need a BOOTP- and a TFTP-server on your host-machine, we use dnsmasq here, since it can provide both services. Install dnsmasq with:

sudo apt-get install dnsmasq

Note that network-manager has a dependency on dnsmasq-base, which will block port 53. Hence, you may need to remove dnsmasq-base, e.g., with

sudo aptitude install dnsmasq dnsmasq-base-

you may need to reinstall dependencies that will be removed in the process. ref. http://ubuntuforums.org/showthread.php?p=12006425

Changes in /etc/dnsmasq.conf:

1. make sure the LAN has internet access:

   ping openwrt.org

2. only listen on the interface which is directly connected to the same LAN like the WAN-port (Eth1/PoE) of the RouterBoard via a layer2 switch, e.g.

   interface=eth0

3. set default gateway, e.g.

   dhcp-option=option:router,192.168.177.1

4. allow a DHCP range which is within netmask of your LAN but does not conflict with other DHCP-service, e.g.

   dhcp-range=192.168.177.2,192.168.177.5,2m

5. allocate an IP address to the board, e.g.

   dhcp-host=00:0C:42:XX:XX:XX,192.168.177.2

   (replace the XX with the MAC address of your board!)
6. enable dnsmasq's built-in TFTP-server

   enable-tftp

7. set the root directory-for files available via TFTP.

   tftp-root=/srv/tftp

8. download initramfs-kernel-image into root-directory of the TFTP-server:

   wget --directory-prefix=/srv/tftp http://downloads.openwrt.org/attitude_adjustment/12.09-beta2/ar71xx/nand/openwrt-ar71xx-nand-vmlinux-initramfs.elf

9. set filename of kernel image for tftp-server/BOOTP:

   dhcp-boot=/srv/tftp/openwrt-ar71xx-nand-vmlinux-initramfs.elf

Finally restart dnsmasq

sudo /etc/init.d/dnsmasq restart

1. Connect to the serial port with a null modem cable (115200, 8N1, no handshaking).
2. Press a key shortly after powering the board.
3. Press o to change the boot device
4. Press 1 to boot from ethernet once.
5. Press x to leave setup (-o-1-x is needed only once, the boot method is saved in non-volatile memory)

If everything is setup correctly it should look like:

\0x00

RouterBOOT booter 2.29

RouterBoard 493G

CPU frequency: 680 MHz
  Memory size: 256 MB

Press any key within 2 seconds to enter setup..
writing settings to flash... OK
trying bootp protocol... OK
Got IP address: 192.168.177.2
resolved mac address 00:14:0B:3F:BB:C3
Gateway: 192.168.177.1
transfer started ............................... transfer ok, time=1.46s
setting up elf image... OK
jumping to kernel code
[    0.000000] Linux version 3.3.8 (renne@renne) (gcc version 4.6.3 20120201 (prerelease) (Linaro GCC 4.6-2012.02) ) #1 Mon Sep 17 12:57:18 CEST 2012
[    0.000000] bootconsole [early0] enabled
[    0.000000] CPU revision is: 00019374 (MIPS 24Kc)
[    0.000000] SoC: Atheros AR7161 rev 2
[    0.000000] Clocks: CPU:680.000MHz, DDR:340.000MHz, AHB:170.000MHz, Ref:40.000MHz
[    0.000000] Determined physical RAM map:
[    0.000000]  memory: 08000000 @ 00000000 (usable)
[    0.000000] User-defined physical RAM map:
[    0.000000]  memory: 10000000 @ 00000000 (usable)
[    0.000000] Initrd not found or empty - disabling initrd
[    0.000000] Zone PFN ranges:
[    0.000000]   Normal   0x00000000 -> 0x00010000
[    0.000000] Movable zone start PFN for each node
[    0.000000] Early memory PFN ranges
[    0.000000]     0: 0x00000000 -> 0x00010000

...

Please press Enter to activate this console. [   21.710000] device eth0 entered promiscuous mode
[   21.720000] device eth1.1 entered promiscuous mode
[   21.720000] device eth1 entered promiscuous mode
[   23.110000] eth0: link up (1000Mbps/Full duplex)
[   23.130000] br-lan: port 1(eth0) entered forwarding state
[   23.130000] br-lan: port 1(eth0) entered forwarding state
[   23.600000] eth1: link up (1000Mbps/Full duplex)
[   23.610000] br-lan: port 2(eth1.1) entered forwarding state
[   23.620000] br-lan: port 2(eth1.1) entered forwarding state
[   25.130000] br-lan: port 1(eth0) entered forwarding state
[   25.620000] br-lan: port 2(eth1.1) entered forwarding state

Press Enter and you are in the console of OpenWRT running from RAM and booted via BOOTP/TFTP.

Note that you may need to set dns servers to get net-access while running the netbooted image. Enter a working dns for you in

vi /tmp/resolv.conf.auto

then restart dnsmasq to make the change effective (cross-check that you indeed have net-access afterwords):

/etc/init.d/dnsmasq restart

You need a working Netboot first, see above.

If you want to install OpenWrt permanently into the NAND flash you once need to erase the NAND flash to get rid of the RouterOS stuff:

1. connect via serial line
2. press a key shortly after powering the RB493G up
3. press e and type yes to format the flash from the bootloader
4. power off the Routerboard

1. Start Netboot (see above).
2. Press ENTER to get a shell prompt.
3. Execute:

wget2nand http://downloads.openwrt.org/attitude_adjustment/12.09/ar71xx/nand/

You can adjust the path-part dependend on the OpenWRT-version ('attitude_adjustment/12.09'), but make sure you use the 'ar71xx/nand/'-branch and at least version '12.09-rc2'.

Use the Permanent-Installation-Guide via BOOTP/TFTP-Netboot from above.

→ Basic configuration After flashing, proceed with this.
Set up your Internet connection, configure wireless, configure USB port, etc.

The default network configuration is:

Interface Name	Description	Default configuration
br-lan (eth0, eth1.1)	LAN	192.168.1.1/24
eth1.2	WAN	DHCP

The default switch configuration is:

Board	Switch	Port	VLAN	Interface
	0	CPU	1
Eth5	0	1	1	eth0
Eth2	0	2	1	eth0
Eth3	0	3	1	eth0
Eth4	0	4	1	eth0
	0	5	off
	1	CPU	1/2
Eth9	1	1	1	eth1.1
Eth6	1	2	1	eth1.1
Eth8	1	3	1	eth1.1
Eth7	1	4	1	eth1.1
Eth1/PoE	1	5	2	eth1.2

→ generic.failsafe

→ hardware.button on howto use and configure the hardware button(s).

The Routerboard 493G has one software reset button.

BUTTON	Event
Reset	reset

The SD-card reader is now supposed to work, but the needed patch is currently not in trunk. You will find the ticket with history here: https://dev.openwrt.org/ticket/12349

Hence precompiled images with working SD-card reader is not yet available from the OpenWrt server. Until that is resolved, you can find compiled kernel and rootfs here: http://ubuntuone.com/1bZTk4vlKwroZezcdeJa4l http://ubuntuone.com/2V1BoearwvvMOsNzUz7mcx

Provide them on a web-server, or copy them manually over to the kernel and rootfs partitions on the nand.

The USB-port of the RB493G is a shameful chapter of Mikrotik engineering.

The USB-standard demands a 5VDC-power-supply on the USB-socket, but Mikrotik tried to save a few cents for a voltage converter. So one has to buy a power-injector from Mikrotik and any 5VDC-power-supply. Pray the plug of your power-supply fits into the power-injector! Just using a powered USB-hub doesn't solve the problem, as USB-hubs only enumerate/register with the host-controller when 5VDC is supplied by the host-controller.

Reliable vendors just update their PCB-layout, but Mikrotik sells that non-standard/sub-standard PCB-layout for years, now.

The Routerboard has a OHCI-controller for USB 1.x and a EHCI-controller for USB 2.0.

See usb.essentials for configuration.

Architecture:	MIPS-BE
Vendor:	Mikrotik / Qualcomm Atheros
Bootloader:	MikroTik RouterBoot (Rescue- and Main-Bootloader)
Default Operating System:	MikroTik RouterOS v4, Level5-license
System-On-Chip:	Atheros AR7161 rev 2
CPU/Speed	MIPS 24Kc rev 00019374 680/800 Mhz
Flash-Chip:	Samsung NAND 128MiB 3,3V 8-bit, ST Micro NAND01GW3B2CN6 or Toshiba NAND 128MiB 3,3V 8-bit
Flash size:	128 MiB NAND-Flash
Micro-SD:	1x Micro-SD-socket (probably SPI)
RAM:	256 MiB DDR-SDRAM
Wireless:	optional via 3x Mini-PCI IIIA/B
Ethernet:	9x 10/100/1000Base-T(X) (2x Atheros AR8316-5-port-switch with VLAN support swconfig
Internet:	n/a/xDSL/DOCSIS/3g/LTE
USB:	1x 2.0 (unpowered)
Serial:	YES 1x Sub-DB9 RS-232C asynchronous
JTAG:	Maybe (contatcs on PCB, not tested)
LED:	Power, NAND activity, 5x user LED
Power options:	10..28 VDC Power-over-Ethernet or Power-Jack
Power consumption:	~3 Watt, up to 10 Watt for MiniPCI-cards, maximum 16 Watt
Dimensions:	160 mm x 105 mm, 189 grams

Enclosure:

Enclosure Mikrotik CA493 with two N-pigtails and -antennas (antennas are ALFA ARS-N19CW, 2.4GHz 9dBi - pigtails and antennas not included in enclosure package)

Front:

Enclosure Mikrotik CA493 with serial port, ethernet-port, LEDs and power-connector of Routerboard RB493G

Back:

Enclosure Mikrotik CA493 with two N-pigtails (not included), multi-purpose hole (e.g. N-connector, Swivel-antenna, …) and ground-screw

Left/Top:

Enclosure Mikrotik CA493 with eight ethernet-ports of Routerboard RB493G

Right:

Enclosure Mikrotik CA493 with venting holes

Bottom:

Enclosure Mikrotik CA493

Enclosure opened:

Enclosure Mikrotik CA493 with two N-pigtails (not included), Routerboard 493G and Routerboard R52nM (Wifi-card)

• To remove the cover just unscrew the 4 screws (2 left side, two right side)

Main PCB

Photo of PCB

Front:

• Power socket
• 2x LED
• 1x 1000Base-T with proprietary POE
• 1x Sub-D9 Serial Port (Console by default)
• 8x 1000Base-T Port
• 1x Reset-contacts
• 2x Atheros AR8316 (under heatsinks)
• 1x JTAG-contacts
• 1x USB 2.0 (unpowered)
• 3x MiniPCI Type IIIA/B
• 2x RAM SAMSUNG K4H510838G-LCCC
• 2x regulated Fan-connector 3.3V 500mA
• 2x regulated Fan connector main voltage 500mA
• 4x Screw holes

Back:

• Flash: ST NAND01GW382CNb
• CPLD: XILINX XC9536XL
• Flash: microSD-Socket
• RAM: 2x SAMSUNG K4H510838G-LCCC

The Routerboard has one serial interface in form of a Sub-D9-socket. By default it provides a serial console. It can be accessed with a Null-Modem-Cable (115200, 8N1, no handshaking!).

There are seven contacts named "JTAG" between USB- and MiniPCI-Socket, but not tested.

→ generic.debrick

In worst case keep "Reset"-button pressed when powering on the Routerboard to access the recovery-boot-loader via serial console. That way the Routerboard can be re-flashed with a RouterOS-image (NPK-file) using the origin MikroTik-Netinstall-software (BOOTP/TFTP).

For some Help with the Tags, please have a look here: tags

1. as a beginner, you really should inform yourself about soldering in general and then even obtain some experience!

Components:

1x	PCB
1x	USB-2.0-dual-A-socket, e.g., |these.
1x	USB-2.0- A-plug, e.g., these.
1x	Traco TSR 1-2450 step-down-converter 5VDC/1A (doesn't need any other components like capacitors or heatsink). As of this writing you will find the LM7805V voltage regulator at DealExtreme
1x	Multifuse 60VDC/0,5A Ihold/1A Itrip

Proto-type and diagrams/layouts aren't beauties, but maybe someone with more Cadsoft-Eagle-experience can make a nice circuit-diagram and a real PCB-layout. Eagle files and datasheets

Rudimentary circuit-diagram with USB-2.0 data-port (1) and generic USB-2.0 charger port (2), both supplied by a step-down-converter via the fan-connector of the RB493G:

Rudimentary PCB-layout, not applicable:

USB-mod prototype top-view:

USB-mod prototype bottom-view:

USB-mod prototype attached: