NOT SUPPORTED!

GPL: http://dlcdnet.asus.com/pub/ASUS/wireless/RT-AC52U/GPL_RT_AC52U_30043804180.zip or https://www.asus.com/uk/Networking/RTAC52U/HelpDesk_Download/ then Others > Others > GPL

RT-AC52U Firmware: http://dlcdnet.asus.com/pub/ASUS/wireless/RT-AC52U/FW_RT_AC52U_30043804180.ZIP

Please check out the article flash.layout. It contains an example and a couple of explanations.

cat /proc/mtd

dev:    size   erasesize  name
mtd0: 000e0000 00020000 "Bootloader"
mtd1: 07f00000 00020000 "UBI_DEV"
mtd2: 0001f000 0001f000 "nvram"
mtd3: 0003e000 0001f000 "Factory"
mtd4: 0003e000 0001f000 "Factory2"
mtd5: 02017000 0001f000 "linux"
mtd6: 01ee1d40 0001f000 "rootfs"
mtd7: 02017000 0001f000 "linux2"
mtd8: 01ee1d40 0001f000 "rootfs2"

btn_rst_gpio=4097
btn_wltog_gpio=4109
btn_wps_gpio=4098
led_all_gpio=4106
led_lan_gpio=12300
led_pwr_gpio=4105
led_usb_gpio=12302
led_wan_gpio=12296
led_wps_gpio=4105

Using Firmware version 3.0.0.4.380.4180

1) cat /proc/version

Linux version 2.6.36 (root@asus) (gcc version 4.2.4) #1 Thu Dec 1 00:49:41 CST 2016

uname -a

Linux RT-AC52U 2.6.36 #1 Thu Dec 1 00:49:41 CST 2016 mips GNU/Linux

2) cat /proc/cpuinfo

system type             : MT7620
processor               : 0
cpu model               : MIPS 24Kc V5.0
BogoMIPS                : 386.04
wait instruction        : yes
microsecond timers      : yes
tlb_entries             : 32
extra interrupt vector  : yes
hardware watchpoint     : yes, count: 4, address/irw mask: [0x0000, 0x0df8, 0x0d78, 0x0ae8]
ASEs implemented        : mips16 dsp
shadow register sets    : 1
core                    : 0
VCED exceptions         : not available
VCEI exceptions         : not available

3) cat /proc/meminfo

        total:    used:    free:  shared: buffers:  cached:
MemTotal:         126220 kB (128MB)
MemFree:           89148 kB
Buffers:            2688 kB
Cached:             7900 kB
SwapCached:            0 kB
Active:             7008 kB
Inactive:           7168 kB
Active(anon):       3700 kB
Inactive(anon):       84 kB
Active(file):       3308 kB
Inactive(file):     7084 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:          3600 kB
Mapped:             2736 kB
Shmem:               196 kB
Slab:              11732 kB
SReclaimable:       1836 kB
SUnreclaim:         9896 kB
KernelStack:         464 kB
PageTables:          368 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:       63108 kB
Committed_AS:       9756 kB
VmallocTotal:    1048372 kB
VmallocUsed:       10528 kB
VmallocChunk:    1029016 kB

5) cat /proc/interrupts

           CPU0
  3:       1020          Ralink  eth2
  4:      62434          Ralink  ra0
  5:     197491          Ralink  timer
  6:          0          Ralink  ralink_gpio
 12:       7771          Ralink  serial
 13:      14974          Ralink  rai0
 17:          0          Ralink  Ralink_ESW
 18:          1          Ralink  ehci_hcd:usb1, ohci_hcd:usb2
ERR:          0

6) ps

  PID USER       VSZ STAT COMMAND
    1 admin     4464 S    /sbin/init
    2 admin        0 SW   [kthreadd]
    3 admin        0 SW   [ksoftirqd/0]
    4 admin        0 SW   [kworker/0:0]
    5 admin        0 SW   [kworker/u:0]
    6 admin        0 SW<  [khelper]
    7 admin        0 SW   [sync_supers]
    8 admin        0 SW   [bdi-default]
    9 admin        0 SW<  [kintegrityd]
   10 admin        0 SW<  [kblockd]
   11 admin        0 SW   [kswapd0]
   12 admin        0 SW   [fsnotify_mark]
   13 admin        0 SW<  [crypto]
   19 admin        0 SW   [mtdblock0]
   20 admin        0 SW   [mtdblock1]
   21 admin        0 SW   [ubi_bgt0d]
   22 admin        0 SW   [mtdblock2]
   23 admin        0 SW   [mtdblock3]
   24 admin        0 SW   [mtdblock4]
   25 admin        0 SW   [mtdblock5]
   26 admin        0 SW   [mtdblock6]
   27 admin        0 SW   [mtdblock7]
   28 admin        0 SW   [mtdblock8]
   29 admin        0 SW   [kworker/u:1]
   36 admin        0 SW   [kworker/0:1]
   48 admin      668 S    hotplug2 --persistent --no-coldplug
   85 admin     4448 S    console
   87 admin        0 SW   [ubifs_bgt0_5]
   88 admin     1604 S    /bin/sh
   92 admin     1588 S    /sbin/syslogd -m 0 -S -O /jffs/syslog.log -s 256 -l 6
   94 admin     1588 S    /sbin/klogd -c 5
  126 admin        0 SW   [RtmpCmdQTask]
  127 admin        0 SW   [RtmpWscTask]
  128 admin        0 SW   [flush-ubifs_0_5]
  147 admin        0 SW   [RtmpCmdQTask]
  148 admin        0 SW   [RtmpWscTask]
  182 admin     4456 S    /sbin/wanduck
  183 admin     4456 S    wlcconnect
  188 admin     4456 S    wpsaide
  205 admin     1600 S    crond
  206 admin     1140 S    /usr/sbin/infosvr br0
  207 admin     4456 S    watchdog
  214 admin     4456 S    ots
  216 admin     1232 S    lld2d br0
  243 admin        0 SW   [khubd]
  319 admin     4456 S    usbled
  374 admin     4456 S    ntp
  382 nobody    1064 S    dnsmasq --log-async
  383 admin     4320 S    httpd
  386 admin     1596 S    telnetd
  392 admin     1016 S    mDNSNetMonitor
  393 admin     1196 S    networkmap
  395 admin     2236 S    u2ec
  396 admin     1236 S    lpd
  397 admin     2236 S    u2ec
  398 admin     2236 S    u2ec
  537 admin     1604 S    -sh
  549 admin     1592 R    ps