EMC branded Mellanox SX60xx switch

Used enterprise IT stuff is stupid cheap in the US. Stupid cheap like 18 port FDR (56Gbits/sec) Infiniband switches shipped to your door for 6.67USD per port. Only a couple of issues with these:

• They run a very limited EMC OS instead of the somewhat more open Linux-based Mellanox MLNX-OS
• No VPI (Ethernet over Infiniband, more or less)
• No subnet manager (facilitates IP over Infiniband)
• Management by telnet ("SSH? That's so not going to happen!")
• It's not Linux

The devices at FnordNet are Mellanox SX6018s wearing EMC colors. (Mellanox ships switches with blue fronts and EMC switches are black.) On the connector side are:

• 18 QSFP 56Gbits/sec Infiniband connectors
• 2 8P8C modular 1000baseT Ethernet connectors (Labelled MGT)
• 1 USB connector
• 1 8P8C modular connector for the serial console (labelled CONSOLE)
• a small recessed reset button switch (small hole on the left side of the connector panel)

Mellanox makes a number of similar devices with the same generation of silicon:

• SX6005 and SX6012 -- 1U, half width, 12 QSFP connectors arranged in two rows of six. SX6005 is the unmanaged version. SX6012 is the managed switch with the subnet manager and single port Ethernet connectivity
• SX6015 and SX6018 -- 1U, full width, 18 QSFP connectors in one row of 18. SX6018 is the managed version with a subnet manager and dual Ethernet management ports
• SX6025 and SX6036 -- 1U, full width, 36 QSFP connectors in two rows of 18. SX6025 is unmanaged. SX6036 is the managed version.

All of these are built on the same Infiniband silicon -- Mellanox SwitchX-2. The management functions on the SX6012, SX6018, and SX6036 are done by an embedded Linux system running on a PowerPC M460EX series CPU attached to the SwitchX-2 silicon over a PCI interface of some sort.

Before breaking it, a diversion into EMC's SwitchOS

At power on time, a tiny bit of hardware initialization is done and then U-Boot (a free as in freedom) bootloader is given control.

Here's what it looks is dumped to the console when power is applied and the automatic boot is interrupted:

U-Boot 2009.01 SX_PPC_M460EX SX_3.2.0330-82-EMC ppc (Feb 27 2013 - 12:13:42)

CPU:   AMCC PowerPC 460EX Rev. B at 1000 MHz (PLB=166, OPB=83, EBC=83 MHz)
       Security/Kasumi support
       Bootstrap Option H - Boot ROM Location I2C (Addr 0x52)
       Internal PCI arbiter disabled
       32 kB I-Cache 32 kB D-Cache
Board: Mellanox PPC460EX Board
FDEF:  No
I2C:   ready
DRAM:   2 GB (ECC enabled, 333 MHz, CL3)
FLASH: 16 MB
NAND:  1024 MiB
PCI:   Bus Dev VenId DevId Class Int
PCIE0: link is not up.
PCIE1: successfully set as root-complex
        01  00  15b3  c738  0c06  00
Net:   ppc_4xx_eth0, ppc_4xx_eth1
Hit any key to stop autoboot:  0 
=>

Nothing too super exciting there, but it does tell us what we're looking at. Note that u-Boot is running and we have its CLI available to use. A little bit more info about the hardware is available using the bdinfo U-Boot command:

=> bdinfo
memstart    = 0x00000000
memsize     = 0x80000000
flashstart  = 0xFF000000
flashsize   = 0x01000000
flashoffset = 0x00000000
sramstart   = 0x00000000
sramsize    = 0x00000000
bootflags   = 0xFFFE0218
intfreq     =   1000 MHz
busfreq     = 166.667 MHz
ethaddr     = 00:02:C9:63:EF:EE
eth1addr    = 00:02:C9:63:EF:EF
IP addr     = 172.17.255.120
baudrate    =   9600 bps
=>

printenv will give a feel for what EMC (before Dell bought them all up) has done pre-boot software wise:

=> printenv
bootcmd=run flash_jffs2
baudrate=9600
loads_echo=
autoload=n
hostname=mlnx460ex
netdev=eth0
nfsargs=setenv bootargs root=/dev/nfs rw nfsroot=${serverip}:${rootpath}
ramargs=setenv bootargs root=/dev/ram rw
addip=setenv bootargs ${bootargs} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}:${netdev}:off panic=1
addtty=setenv bootargs ${bootargs} console=ttyS0,${baudrate}
addmisc=setenv bootargs ${bootargs}
initrd_high=30000000
kernel_addr_r=400000
fdt_addr_r=800000
ramdisk_addr_r=C00000
hostname=mlnx460ex
ramdisk_file=mlnx460ex/uRamdisk
rootpath=/opt/eldk/ppc_4xxFP
flash_self=run ramargs addip addtty addmisc;bootm ${kernel_addr} ${ramdisk_addr} ${fdt_addr}
flash_nfs=run nfsargs addip addtty addmisc;bootm ${kernel_addr} - ${fdt_addr}
net_nfs=tftp ${kernel_addr_r} ${bootfile}; tftp ${fdt_addr_r} ${fdt_file}; run nfsargs addip addtty addmisc;bootm ${kernel_addr_r} - ${fdt_addr_r}
net_self_load=tftp ${kernel_addr_r} ${bootfile};tftp ${fdt_addr_r} ${fdt_file};tftp ${ramdisk_addr_r} ${ramdisk_file};
net_self=run net_self_load;run ramargs addip addtty addmisc;bootm ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r}
fdt_file=mlnx460ex/mlnx460ex.dtb
flash_self_old=run ramargs addip addtty addmisc;bootm ${kernel_addr} ${ramdisk_addr}
flash_nfs_old=run nfsargs addip addtty addmisc;bootm ${kernel_addr}
net_nfs_old=tftp ${kernel_addr_r} ${bootfile};run nfsargs addip addtty addmisc;bootm ${kernel_addr_r}
load=tftp 200000 mlnx460ex/u-boot.bin
update=protect off 0xFFFA0000 FFFFFFFF;era 0xFFFA0000 FFFFFFFF;cp.b ${fileaddr} 0xFFFA0000 ${filesize};setenv filesize;saveenv
upd=run load update
dhcp_vendor-class-identifier=bootmfg:hwname:mlnx460ex:
clear_filesize=setenv filesize
mfg_dir=mlnx460ex
mfg_args=setenv bootargs root=/dev/ram rw ramdisk_size=${mfg_ramdisk_size} ${mfg_extra_args}
mfg_common_args=run addtty addmisc
mfg_load=tftp ${kernel_addr_r} ${mfg_root}${mfg_dir}/${mfg_kernel_file};tftp ${fdt_addr_r} ${mfg_root}${mfg_dir}/${mfg_fdt_file};tftp ${ramdisk_addr_r} ${mfg_root}${mfg_dir}/${mfg_ramdisk_file}
mfg_nodhcp=echo "Manufacture will TFTP from directory ${mfg_root}${mfg_dir}, and boot";echo; run clear_filesize ; run mfg_load;if test 0${filesize} -gt 0; then echo Booting mfg ; run mfg_args mfg_common_args;bootm ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r} ; else ; echo Failed mfg load ; fi
mfg=echo "Manufacture will DHCP, TFTP from directory ${mfg_root}${mfg_dir}, and boot";echo; dhcp; run clear_filesize ; run mfg_load;if test 0${filesize} -gt 0; then echo Booting mfg ; run mfg_args mfg_common_args;bootm ${kernel_addr_r} ${ramdisk_addr_r} 
${fdt_addr_r} ; else ; echo Failed mfg load ; fi
menu_file=menu.img
menu_load=tftp ${menu_addr_r} ${mfg_root}${mfg_dir}/${menu_file}; if test $? -ne 0; then run clear_filesize ; echo Download failed ;fi
menu_usb_load_ext2=usb start; ext2load usb ${mfg_usb_dev}:${mfg_usb_part} ${menu_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${menu_file};
menu_usb_load_fat=usb start; fatload usb ${mfg_usb_dev}:${mfg_usb_part} ${menu_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${menu_file};
menu_usb_load=if test "x${mfg_usb_fstype}" = "xext2"; then run menu_usb_load_ext2 ; else ; run menu_usb_load_fat ; fi
menu_nodhcp=run clear_filesize ; run menu_load ; if test 0${filesize} -gt 0; then autoscr ${menu_addr_r}; else ; echo Failed menu load ; fi
menu=dhcp ; run clear_filesize ; run menu_load ; if test 0${filesize} -gt 0; then autoscr ${menu_addr_r}; else ; echo Failed menu load ; fi
fw_file=u-boot.bin
fw_load=tftp ${fw_addr_r} ${mfg_root}${mfg_dir}/${fw_file}; if test $? -ne 0; then run clear_filesize ; echo Download failed ;fi
fw_usb_load_ext2=usb start; ext2load usb ${mfg_usb_dev}:${mfg_usb_part} ${fw_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${fw_file};
fw_usb_load_fat=usb start; fatload usb ${mfg_usb_dev}:${mfg_usb_part} ${fw_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${fw_file};
fw_usb_load=if test "x${mfg_usb_fstype}" = "xext2"; then run fw_usb_load_ext2 ; else ; run fw_usb_load_fat ; fi
fw_update_raw=protect off 0xFFFA0000 FFFFFFFF;erase 0xFFFA0000 FFFFFFFF;cp.b ${fw_addr_r} 0xFFFA0000 ${filesize};cmp.b ${fw_addr_r} 0xFFFA0000 ${filesize};setenv filesize; saveenv
fw_usb_update=run clear_filesize ; run fw_usb_load ; if test 0${filesize} -gt 0; then run fw_update_raw ; else ; echo Failed update load ; fi
fw_update_nodhcp=run clear_filesize ; run fw_load ; if test 0${filesize} -gt 0; then run fw_update_raw ; else ; echo Failed update load ; fi
fw_update=dhcp ; run clear_filesize ; run fw_load ; if test 0${filesize} -gt 0; then run fw_update_raw ; else ; echo Failed update load ; fi
boot_common_args=run addtty addmisc
mfg_usb_dir=mlnx460ex
mfg_usb_load_ext2=usb start; echo "Loading ${mfg_kernel_file}";ext2load usb ${mfg_usb_dev}:${mfg_usb_part} ${kernel_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${mfg_kernel_file};echo "Loading ${mfg_fdt_file}"; ext2load usb ${mfg_usb_dev}:${mfg_usb_part} ${fdt_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${mfg_fdt_file};echo "Loading ${mfg_ramdisk_file}"; ext2load usb ${mfg_usb_dev}:${mfg_usb_part} ${ramdisk_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${mfg_ramdisk_file}
mfg_usb_load_fat=usb start; echo "Loading ${mfg_kernel_file}";fatload usb ${mfg_usb_dev}:${mfg_usb_part} ${kernel_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${mfg_kernel_file};echo "Loading ${mfg_fdt_file}"; fatload usb ${mfg_usb_dev}:${mfg_usb_part} ${fdt_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${mfg_fdt_file};echo "Loading ${mfg_ramdisk_file}"; fatload usb ${mfg_usb_dev}:${mfg_usb_part} ${ramdisk_addr_r} ${mfg_usb_root}${mfg_usb_dir}/${mfg_ramdisk_file}
mfg_usb_load=if test "x${mfg_usb_fstype}" = "xext2"; then run mfg_usb_load_ext2 ; else ; run mfg_usb_load_fat ; fi
mfg_usb=echo "Manufacture will load from USB directory ${mfg_usb_root}${mfg_usb_dir}, and boot"; echo; run clear_filesize ; run mfg_usb_load; if test 0${filesize} -gt 0; then echo Booting mfg ; run mfg_args mfg_common_args;bootm ${kernel_addr_r} ${ramdisk_addr_r} 
${fdt_addr_r} ; else ; echo Failed mfg load ; fi
kernel_addr=ff000000
fdt_addr=ff1e0000
ramdisk_addr=ff200000
fw_addr_r=400000
menu_addr_r=B00000
pciconfighost=1
pcie_mode=RP:RP
autoload=no
rootdev=/dev/mtdblock6
boot_usb_ext2_loc_1=run usb_args_loc_1 boot_common_args;echo "Loading ${boot_kernel_file}";ext2load usb ${boot_usb_dev}:${boot_usb_part_loc_1} ${kernel_addr_r} ${boot_usb_root}${boot_usb_dir}/${boot_kernel_file};echo "Loading ${boot_fdt_file}";ext2load usb ${boot_usb_dev}:${boot_usb_part_loc_1} ${fdt_addr_r} ${boot_usb_root}${boot_usb_dir}/${boot_fdt_file};bootm ${kernel_addr_r} - ${fdt_addr_r}
boot_usb_ext2_loc_2=run usb_args_loc_2 boot_common_args;echo "Loading ${boot_kernel_file}";ext2load usb ${boot_usb_dev}:${boot_usb_part_loc_2} ${kernel_addr_r} ${boot_usb_root}${boot_usb_dir}/${boot_kernel_file};echo "Loading ${boot_fdt_file}";ext2load usb ${boot_usb_dev}:${boot_usb_part_loc_2} ${fdt_addr_r} ${boot_usb_root}${boot_usb_dir}/${boot_fdt_file};bootm ${kernel_addr_r} - ${fdt_addr_r}
boot_usb_fat_loc_1=run usb_args_loc_1 boot_common_args;echo "Loading ${boot_kernel_file}";fatload usb ${boot_usb_dev}:${boot_usb_part_loc_1} ${kernel_addr_r} ${boot_usb_root}${boot_usb_dir}/${boot_kernel_file};echo "Loading ${boot_fdt_file}";fatload usb ${boot_usb_dev}:${boot_usb_part_loc_1} ${fdt_addr_r} ${boot_usb_root}${boot_usb_dir}/${boot_fdt_file};bootm ${kernel_addr_r} - ${fdt_addr_r}
boot_usb_fat_loc_2=run usb_args_loc_2 boot_common_args;echo "Loading ${boot_kernel_file}";fatload usb ${boot_usb_dev}:${boot_usb_part_loc_2} ${kernel_addr_r} ${boot_usb_root}${boot_usb_dir}/${boot_kernel_file};echo "Loading ${boot_fdt_file}";fatload usb ${boot_usb_dev}:${boot_usb_part_loc_2} ${fdt_addr_r} ${boot_usb_root}${boot_usb_dir}/${boot_fdt_file};bootm ${kernel_addr_r} - ${fdt_addr_r}
mfg_kernel_file=vmlinuz
mfg_ramdisk_file=rootfs
mfg_ramdisk_size=180224
mfg_fdt_file=fdt
mfg_usb_dev=0
mfg_usb_part=1
mfg_usb_fstype=fat
mfg_usb_root=/
boot_kernel_file=vmlinuz
boot_fdt_file=fdt
boot_usb_dev=0
boot_usb_part_loc_1=2
boot_usb_part_loc_2=3
boot_usb_root_loc_1=/dev/sda5
boot_usb_root_loc_2=/dev/sda6
usb_args_loc_1=setenv bootargs root=${boot_usb_root_loc_1} ro reset_button=${reset_button} rootdelay=8 ${image_kernel_args} ${extra_args}
usb_args_loc_2=setenv bootargs root=${boot_usb_root_loc_2} ro reset_button=${reset_button} rootdelay=8 ${image_kernel_args} ${extra_args}
jffs2_args=setenv bootargs root=${rootdev} rootfstype=jffs2 ro reset_button=${reset_button} ${image_kernel_args} ${extra_args}
mfg_extra_args=ramdisk=65536
ethaddr=00:02:C9:63:EF:EE
eth1addr=00:02:C9:63:EF:EF
ethact=ppc_4xx_eth0
bootfile=pxelinux.0
emc_fabric=B
autoscr=no
filesize=175B
fileaddr=400000
gatewayip=10.10.4.1
netmask=255.255.252.0
ipaddr=172.17.255.120
serverip=172.17.255.252
script_rev=3.3.0
script_date=7.12.13
autostart=yes
bootdelay=5
emcram_addr=400000
emcfl_one_start=ff400000
emcfl_one_end=ff5fffff
emcfl_two_start=ff600000
emcfl_two_end=ff7fffff
emcload_addr=ff400000
load_dir=.
binary_name=ibsw.bin.load
restore_defaults=setenv load_dir .; setenv binary_name ibsw.bin.load; saveenv;
setip_176=setenv ipaddr 192.168.176.190; setenv serverip 192.168.176.253; saveenv
setip_177=setenv ipaddr 192.168.177.191; setenv serverip 192.168.177.253; saveenv
setip_linux=setenv ipaddr 192.168.10.10; setenv serverip 192.168.10.1; saveenv
setip_16=setenv ipaddr 172.16.255.120; setenv serverip 172.16.255.252; saveenv
setip_17=setenv ipaddr 172.17.255.120; setenv serverip 172.17.255.252; saveenv
set_fab_a=setenv emc_fabric A; saveenv
set_fab_b=setenv emc_fabric B; saveenv
emcpxe=tftp ${emcram_addr} ${load_dir}/${binary_name}
emcflash=ping $serverip; bootm ${emcload_addr}
mlxlinux=run jffs2_args boot_common_args;bootm ${kernel_addr} - ${fdt_addr}
flash_jffs2=run emcflash
menu_usb=run emcflash
emcburn_one=prot off ${emcfl_one_start} ${emcfl_one_end}; erase ${emcfl_one_start} ${emcfl_one_end}; setenv autostart no; tftp ${emcram_addr} ${load_dir}/${binary_name}; iminfo ${emcram_addr}; cp.b ${emcram_addr} ${emcfl_one_start} ${filesize}; iminfo 
${emcfl_one_start}; setenv autostart yes; prot on ${emcfl_one_start} ${emcfl_one_end};
emcburn_two=prot off ${emcfl_two_start} ${emcfl_two_end}; erase ${emcfl_two_start} ${emcfl_two_end}; setenv autostart no; tftp ${emcram_addr} ${load_dir}/${binary_name}; iminfo ${emcram_addr}; cp.b ${emcram_addr} ${emcfl_two_start} ${filesize}; iminfo 
${emcfl_two_start}; setenv autostart yes; prot on ${emcfl_two_start} ${emcfl_two_end};
emcload_one=setenv emcload_addr ${emcfl_one_start}; saveenv
emcload_two=setenv emcload_addr ${emcfl_two_start}; saveenv
script_get=setenv autostart no; tftp ${emcram_addr} uboot_start_script.img; setenv autostart yes; imi ${emcram_addr};
script_exe=autoscr ${emcram_addr}
boot_emcpxe=setenv flash_jffs2 run emcpxe; setenv menu_usb run emcpxe; saveenv
boot_emcflash=setenv flash_jffs2 run emcflash; setenv menu_usb run emcflash; saveenv
boot_mlxlinux=setenv flash_jffs2 run mlxlinux; setenv menu_usb run mlxlinux; saveenv
emchelp=echo All commands are preceeded by \"run \"; echo setip_176 ...... set ip and server ip to 192.176 subnet; echo setip_177 ...... set ip and server ip to 192.177 subnet; echo setip_16 ....... set ip and server ip to 172.16 subnet; echo setip_17 ....... set 
ip and server ip to 172.17 subnet;echo setip_linux .... set ip and server ip to linux default (10.10); echo emcburn_one .... burn ibsw.bin.load to the first symmk flash location;echo emcburn_two .... burn ibsw.bin.load to the second symmk flash location;echo 
emcload_one .... set emcflash to point to the first symmk flash location;echo emcload_two .... set emcflash to point to the second symmk flash location;echo script_get ..... Load a new version of the uboot_start_script.img;echo script_exe ..... Execute the script 
loaded by script_get (check CRC first!);echo script_status .. Dump revision and build date of last run script; echo boot_emcpxe .... Set PXE boot to be the default boot;echo emcpxe ......... Run PXE boot (just this time); echo boot_emcflash .. Set the Symmk in 
flash to be the default boot;echo emcflash ....... Boot (just this time) from flash;echo boot_mlxlinux .. Set the MLX linux version to be the default boot;echo mlxlinux ....... Run MLX linux (just this time);echo set_fab_a ...... Set switch to be fabric A; echo 
set_fab_b ...... Set switch to be fabric B
script_status=echo Last Script Executed; echo Script Revision: 3.3.0; echo Script Built on: 7.12.13;
stdin=serial
stdout=serial
stderr=serial
reset_button=0
ver=U-Boot 2009.01 SX_PPC_M460EX SX_3.2.0330-82-EMC ppc (Feb 27 2013 - 12:13:42)

Environment size: 12502/16380 bytes
=>

All that was just the bootloader. Where's SwitchOS?

So, yeah. Last section is poorly named. Remember how the autoboot process was stopped last time? Well, here's what we get without interrupting it...

[...]
Hit any key to stop autoboot:  0 
Waiting for PHY auto negotiation to complete... done
ENET Speed is 1000 Mbps - FULL duplex connection (EMAC0)
Using ppc_4xx_eth0 device
ping failed; host 172.17.255.252 is not alive
   Loading Kernel Image ... OK
ABCDEFdrv_table_install:         syslog at 0x00033d84 with minor  0 (DRV_SETUP) (DRV_INIT)
drv_table_install:         isrlog at 0x00033d84 with minor  1 (DRV_INIT)
drv_table_install:  userinterface at 0x00004db0 with minor  0 (DRV_SETUP) (DRV_INIT)
drv_table_install:          stty0 at 0x0006e804 with minor  0 (DRV_SETUP) (DRV_INIT)
drv_table_install:           eth0 at 0x0006f194 with minor  0 (DRV_SETUP) (DRV_INIT)
drv_table_install:           i2c0 at 0x00079d94 with minor  0 (DRV_SETUP) (DRV_INIT)
drv_table_install:           i2c1 at 0x00079d94 with minor  1 (DRV_INIT)
drv_table_install:         itcpip at 0x0003c05c with minor  0tcpipInit: Starting internal TCP/IP stack.
 (DRV_SETUP) (DRV_INIT)
kernel_main: Drivers installed, installing INIT process with stack size = 8192.
Bar [ 0 ] is the first memory bar
sk_init_main: Starting process based initialization - 8590.
02:60:48:10:ff:78 UDP socket 3 created
TCP socket 4 created
sk_init_main: Process based initialization complete - 8590.
sk_init_main: Installing task table.
task_table_install:        console at 0x00015c24 stack 0x00452410/26624 : 4
task_table_install:          inetd at 0x000359a0 stack 0x00470c10/8192 : 5
task_table_install:       poll_cqs at 0x000aa44c stack 0x00458c10/8192 : 6
task_table_install:     poll_ports at 0x000aa584 stack 0x0045ac10/8192 : 7
task_table_install:        env_mon at 0x00082f94 stack 0x0045ec10/8192 : 8
task_table_install:    env_bin_api at 0x000143a0 stack 0x00460c10/8192 : 9
task_table_install: incoming_fw_files at 0x00013e84 stack 0x00462c10/8192 : 10
sk_init_main: Task table installed.  Starting tasks and exiting.
----------------------------- Board Info -----------------------------
* Chasis Type         : STINGRAY
* Number of Ports     : 18
* U-Boot Revision     : 3.2.330
* Firmware Revision   : 9.9.1030
* INI file Revision   : 0x21010009
* SwitchOS Revision   : 1.282
* SwitchOS Build Date : 2013-07-23
* SwitchOS Build Time : 15:40:30
* SwitchOS Build Path : /emc/tdowning/ppc460_release/july_23_2013
----------------------------------------------------------------------
15:33:09 12/16/2017
Switch-B(4)>

It almost looks like it's going to netboot if it can find a server to give it an image. But we don't have one and that's totally OK. The Switch-B(4)> is the CLI prompt. There's a help command that lists available commands, but it does not provide a lot of detail. But here are a few potentially useful commands:

• env show inventory lists out vital product data (VPD) for the replaceable components: switch chassis, power supplies, and fan boards
• env show fans how fast are they spinning? 0 is probably not good
• env set uid led blink will blink the blue LED on the left side on the switch's connector panel -- useful for finding the switch you want to work on
• env set port bad led on is much the same, but activates an orange LED just above the blue UID indicator
• baz swportinfo 1 will provide port statistics and the like. Change 1 to the number of the switch port of interest
• build info about the software build
• board a little bit about the hardware
• info a bit about the hardware and SwitchOS
• env show alarms pretty much self explanatory

Putting MLNX-OS on it

As mentioned above, I desire to have a real OS on these switches. Found some leads over on https://forums.servethehome.com/ which said conversion is possible, but "PM me for more details." The following is a translation of the nice gentleman's "Mellanox Switch Conversion Guide" document into the procedure I have used.

Pre-requisiteses

(Yes. I know I misspelled that.)

• console cable for switch (Cisco cables work fine) 9600 bps 8n1 works here.
• serial comms program (C-Kermit and I get along just fine. Others may use screen. Or minicom. Or Teraterm. Or HyperTerminal. Or for people with long memories, even {COMMO} or Telix or Qmodem.)
• Willingness to root around typing stuff into a text console fiddle with unsupported softwares
• A MLNX-OS binary distribution for the switch in question. Try:
  • http://www.mellanox.com/downloads/Software/image-PPC_M460EX-3.6.1002.img or
  • http://www.mellanox.com/downloads/Software/image-PPC_M460EX-3.6.2102.img or
  • http://www.mellanox.com/downloads/Software/image-PPC_M460EX-3.6.3004.img
• a hex editor (we'll be picking apart some binary archives at some point)
• some time
• some willingness to violate software licenses
• attention to detail: breaking the U-Boot image inside the switch is likely to result in a need for I2C tools to make things work again. This is not something I want to deal with.

Make switch not boot automatically

Apply power, interrupt autoboot, run

=> setenv autostart off
=> setenv autoload off
=> saveenv

We'll revert that by running

=> setenv autostart yes
=> setenv autoload n
=> saveenv

at some point later on. (Those are the settings as the switch arrived.)

Get bootable bits from MLXN-OS

The image-PPC_M460EX-3.6.1002.img OS images are actually ZIP archives containing a compressed tar file image-PPC_M460EX-ppc-m460ex-20160609-202426.tgz and some package meta-data that we do not need. From image-PPC_M460EX-ppc-m460ex-20160609-202426.tgz, extract the kernel image and device tree files:

$ gzip -dc image-PPC_M460EX-ppc-m460ex-20160609-202426.tgz | tar xvvf - ./boot/vmlinuz-uni ./boot/fdt-uni

And copy boot/vmlinuz-uni and boot/fdt-uni to a TFTP server that the switch will be able to retrieve these files from. Since my switch has an IP address of 172.17.255.120 as it was delivered, I'm simply adding a secondary IP address to the existing TFTP server instead of changing the switch's IP address.