D-Link DSL-524T

This device is NOT RECOMMENDED for future use with OpenWrt due to low flash/ram.
DO NOT BUY DEVICES WITH 4MB FLASH / 32MB RAM if you intend to flash an up-to-date and secure OpenWrt version onto it! See 4/32 warning for details.

1) This device does not have sufficient resources (flash and/or RAM) to provide secure and reliable operation.
This means that even setting a password or changing simple network settings might not be possible any more, rendering the device effectively useless. See OpenWrt on 4/32 devices what you can do now.

2) OpenWrt support for this device has ended in 2022.
19.07.10 was the last official build for 4/32 devices.

D-Link DSL-524T ADSL2/2+ Router

Version/Model S/N OpenWrt Version Supported Model Specific Notes
A1 (EU) ESL524TEU.A1G 8.09+ Tested to work with 14.07, does NOT work with 15.05 ADM6996M switch
A1 (EU) - 8.09+ IP175A switch

The H/W version is written on a sticker on the bottom of the box.

There is an Annex B (ADSL over ISDN) version of this router, the DSL-584T. It works with the same firmware and is being currently tested.

CPU Ram Flash Network USB Serial JTag
TI AR7 (TNETD7300)@150MHz 16MB 4MB 4 x 1 + ADSL2/2+ No Yes Yes

The DSL-524T is an evolution of the previous ADSL1-only DSL-504T (edit: at least some 504T were adsl2 capable, modern firmware is needed, like the one here: ftp://ftp.dlink.ru/pub/ADSL/DSL-504T/Firmware/ADSL2_plus/AnnexM/ I had one at home syncing at 13Mb/s). The same board is used for the wireless-enabled DSL-G624T (the 524T board has empty solders point for the VLYNQ ACX wireless card).

NOTE: Tests of a DSL-524T with 10.03 version of openwrt on a ADSL 2+ line showed:

      US Connection Rate:     932     DS Connection Rate:     7596

On the same line a DSL-504T with firmware version V3.02B01T01.RU.20071221 showed:

      US Connection Rate:     932     DS Connection Rate:     12976

NOTE: AR7 modems have a reputation of running HOT and the 524T is no exception, so if you're planning to run it for any lenght of time, attaching an heatsink to the CPU might be a good idea. Heat production varies between samples, but the two 524T I've used had no problems in running 24/7 for months.

NOTE: After some months of operation, the ethernet switch included in some 5xxT starts to become unreliable (you'll notice a lot of retransmissions and a much slower connection). One workaround is to force the switch to operate in 10Mb/s mode (unfortunately this requires a kernel patch). This is the same as the problem described here: https://forum.openwrt.org/viewtopic.php?id=8117

This is actually caused by the cheap electrolytic capacitors that smooth the power supply to the switch IC, which degrade over time (and with heat). Replacing the capacitors fixes the problem. Look for a capacitor of about 100uF, one near each short side of the switch IC (IP175), and replace with the same rating.

flash.layout. We have to change some offsets to be able to start OpenWrt on this device.

D-Link DSL-524T OEM
partition start end size Name
mtd2 0x90000000 0x90010000 64 KiB Bootloader
mtd1 0x90010090 0x90091000 ~516 KiB Kernel
mtd0 0x90091000 0x903f0000 3452 KiB Root filesystem
mtd3 0x903f0000 0x90400000 64 KiB Configuration
mtd4 0x90010000 0x903f0000 3968 KiB --

NOTE: mtd4 covers both mtd1 and mtd0

The mtd2 partition contains the bootloader. Never touch it.

The mtd3 partition contains both the bootloader configuration and the original firmware settings. OpenWrt will ignore anything written in here. Do not touch it.

To use OpenWrt on this unit we need to modify the partition layout as follows (changes are in bold):

D-Link DSL-524T and OpenWrt
partition Name start end Description
mtd2 loader 0x90000000 0x90010000 Bootloader (ADAM2)
mtd1 linux 0x90010000 0x90086b80 Linux kernel
mtd0 rootfs 0x90086b80 0x903f0000 Read-only squashfs + jffs2 filesystem
mtd3 config 0x903f0000 0x90400000 Original firmware configuration
mtd4 rootfs_data 0x90010000 0x903f0000

Take note: In order to be able to flash Backfire (10.03.1), this partitioning had to be used instead:

D-Link DSL-524T and OpenWrt
partition Name start end size Description
mtd2 loader 0x90000000 0x90010000 64 KiB Bootloader (ADAM2)
mtd1 linux 0x90010000 0x903f0000 3968 KiB Linux kernel
mtd0 rootfs 0x900a1000 0x903f0000 3388 KiB Read-only squashfs + jffs2 filesystem
mtd3 config 0x903f0000 0x90400000 64 KiB Original firmware configuration
mtd4 rootfs_data 0x90010000 0x903f0000 3968 KiB

To be more precise, the kernel, once booted, will map another “virtual” partiton as /dev/mtdblock4 that will point to the newly created jffs2 partition located inside mtd3. Just ignore it for this discussion.

Note: technically, the end offset of mtd1 and the start offset of mtd0 should be calculated based on the size of your kernel image. Don't worry too much about it, the values found here have been found to work reliably. Note 2: In fact, the divide between mtd1 and mtd0 doesn't matter at all when using Openwrt - the firmware will auto-detect the beginning of the rootfs. Other tutorials recommend setting mtd1 to 0x90010000-0x903f0000.

The 524T uses an ADAM2 bootloader. ADAM2 runs an FTP (FTP, not TFTP!) server. Follow generic.flashing and generic.flashing.ftp or read on:

We'll use the openwrt-ar7-squashfs.bin image from the “ar7” OpenWrt port.

Note: If you use 8.09, note that the ADSL interface (wan) won't be started automatically on boot. A simple “ifup wan” will suffice). This bug is fixed in 10.03. (Bug #2781)

  • First of all, we need to know the IP address the bootloader is listening on at startup, which can (and usually is) different from the one used by the original firmware or by OpenWrt. The easiest way to find is to login via telnet to the router running it's original firmware and cat /proc/ticfg/env looking for the my_ipaddress variable (by default it should be set to
  • Then, configure your computer using a static IP address on the same subnet as the bootloader ( should be fine).
  • Reboot the router and use a command-line FTP client to connect to ADAM2 using the my_ipaddress found before. If it doesn't work, reboot the router and try again, the bootloader will listen for a few seconds before loading the system.
  • Login into the server using username ADAM2 and password ADAM2. (If you get “Not logged in, user or password incorrect.” message, type both username and password with lowercase.)
  • Just to be sure, check that the default partition values match the ones described above (write down them somewhere if you'll ever need to flash the original firmware back):
quote "GETENV mtd0"
quote "GETENV mtd1"
quote "GETENV mtd2"
quote "GETENV mtd3"
quote "GETENV mtd4"
  • Set the new partition values
quote "SETENV mtd0,0x90086B80,0x903f0000"
quote "SETENV mtd1,0x90010000,0x90086B80"
  • And flash it
quote "MEDIA FLSH"
put "openwrt-ar7-squashfs.bin" "c mtd4"
quote "REBOOT"
  • After the reboot, OpenWrt should be listening on its default IP address

Note: It might seem stuck just after the “put” command before the transfer starts, just keep waiting for a few minutes. Also, there are strange interactions between ADAM2 and recent Linux kernels (there might be a *lot* of retransmissions which will slow down the process considerably). If flashing from Linux, try this:

  1. Running FTP as root should avoid retransmissions (it allows the FTP client to use different socket options and timeouts).
  2. However, the previous advice works only sometimes. According to this topic, ftp client in Linux uses an enhanced recovery algorithm for TCP retransmission timeouts, which activates the delay increases to 2min (⇒ 256 effective bytes every 2 minutes). This command switches the algorithm off (run as root):
echo 0 > /proc/sys/net/ipv4/tcp_frto

According to this topic, the solution under Windows (works under XP and 7) is quite simple, too - run regedit, find this path:


and add/edit a REG_DWORD value named TcpMaxDataRetransmissions with a value of 40 (hexadecimal). The result - fully qualified name should look like this:


generic.sysupgrade does NOT support this device yet. So the way to upgrade the firmware is using the mtd tool:

mtd write /tmp/openwrt-ar7-squashfs.bin linux && reboot

If you're using the LuCI web interface, its default system upgrade page should work.


NOTE: The ADSL modem requires a pppoa or pppoe section AND please remember to include the appropriate ATM driver in your image (if you build yourself).

Architecture MIPS (little endian)
Vendor D-Link
Bootloader ADAM2
System-On-Chip TI AR7 TNETD7300AZDW (6BZHT99)
CPU Speed 150 MHz
Flash Size 4 MiB
Flash-Chip Spansion S29AL032D90TFI04
RAM Size 16 MiB
RAM-Chip HYNIX HY57V281620ETP-H, 128Mb syncronous DRAM - 2M x 4Bank x16 I/O 16 MiB
Wireless (none)
Ethernet ADM6996M
ADSL TI AR7, ADSL2/2+ (up to 24Mbit/s)
Serial Yes, 3.3V (the kernel finds 2 serial ports)
Power supply 12V, 1.2A

Note: This (might) void your warranty!

The 524T is pretty easy to open, there are just two screws under the case. No warranty stickers in the way!

Once opened, two more screws (and the backpanel) hold the board to the case. There isn't anything interesting on the bottom of the PCB, though.

Note the empty space for the ACX-111 wireless card used in its bigger brother G624T/G684T.

JP6 (5 pins) represents one serial port (3.3V), the only JP with a header soldered. When looking on the LEDs (front) and having the power and ethernet ports on the back JP6 is on the right and has the following pin-out from left to right:

  • TX
  • GND
  • Vcc (3.3V)
  • GND
  • RX

Refer to the DSL-624T's serial section for the correct way to interface it with a DTE over an RS-232 serial port.

The bootloader is using 38400 baud, 8 bits, no parity, 1 stop-bit (38400 8n1):

ADAM2 Revision 0.22.02_b04_Mar 10 2005
(C) Copyright 1996-2003 Texas Instruments Inc. All Rights Reserved.
(C) Copyright 2003 Telogy Networks, Inc.                                     
Usage: setmfreq [-d] [-s sys_freq, in MHz] [cpu_freq, in MHz]                
Memory optimization Complete!                                                
Adam2_AR7DB >                                                                
Press any key to abort OS load, or wait 7 seconds for OS to boot...          

The 524T appears to have a JTAG header (untested). See JTAG tools and port.jtag for more details.

The default network configuration is:

Interface Name Description Default configuration
br-lan LAN
eth0 LAN ports (1 to 4) None
ppp0 WAN port (ADSL) -

Unfortunately the driver for the ADM switch doesn't seem to support VLANs.

alessandro@localhost:~$ telnet
Connected to
Escape character is '^]'.
 === IMPORTANT ============================
  Use 'passwd' to set your login password
  this will disable telnet and enable SSH

BusyBox v1.15.3 (2011-11-24 00:44:13 CET) built-in shell (ash)
Enter 'help' for a list of built-in commands.

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 Backfire (10.03.1, r29592) ------------------------
  * 1/3 shot Kahlua    In a shot glass, layer Kahlua 
  * 1/3 shot Bailey's  on the bottom, then Bailey's, 
  * 1/3 shot Vodka     then Vodka.
root@OpenWrt:/# dmesg
Linux version (jow@nd-build-02.linux-appliance.net) (gcc version 4.3.3 (GCC) ) #5 Wed Dec 21 01:54:33 CET 2011
bootconsole [early0] enabled
CPU revision is: 00018448 (MIPS 4KEc)
TI AR7 (TNETD7300), ID: 0x0005, Revision: 0x27
Determined physical RAM map:
 memory: 01000000 @ 14000000 (usable)
Initrd not found or empty - disabling initrd
Zone PFN ranges:
  Normal   0x00014000 -> 0x00015000
Movable zone start PFN for each node
early_node_map[1] active PFN ranges
    0: 0x00014000 -> 0x00015000
On node 0 totalpages: 4096
free_area_init_node: node 0, pgdat 9438bc40, node_mem_map 943c8000
  Normal zone: 32 pages used for memmap
  Normal zone: 0 pages reserved
  Normal zone: 4064 pages, LIFO batch:0
Built 1 zonelists in Zone order, mobility grouping off.  Total pages: 4064
Kernel command line: rootfstype=squashfs,jffs2 console=ttyS0,38400n8
PID hash table entries: 64 (order: -4, 256 bytes)
Dentry cache hash table entries: 2048 (order: 1, 8192 bytes)
Inode-cache hash table entries: 1024 (order: 0, 4096 bytes)
Primary instruction cache 16kB, VIPT, 4-way, linesize 16 bytes.
Primary data cache 16kB, 4-way, VIPT, no aliases, linesize 16 bytes
Memory: 12352k/16384k available (2255k kernel code, 4032k reserved, 353k data, 136k init, 0k highmem)
Hierarchical RCU implementation.
Clocks: prediv: 1, postdiv: 1, mul: 10
Calibrating delay loop... 149.50 BogoMIPS (lpj=747520)
Mount-cache hash table entries: 512
NET: Registered protocol family 16
bio: create slab <bio-0> at 0
Switching to clocksource MIPS
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 512 (order: 0, 4096 bytes)
TCP bind hash table entries: 512 (order: -1, 2048 bytes)
TCP: Hash tables configured (established 512 bind 512)
TCP reno registered
NET: Registered protocol family 1
squashfs: version 4.0 (2009/01/31) Phillip Lougher
Registering mini_fo version $Id$
JFFS2 version 2.2. (NAND) (SUMMARY)  © 2001-2006 Red Hat, Inc.
msgmni has been set to 24
io scheduler noop registered
io scheduler deadline registered (default)
Serial: 8250/16550 driver, 2 ports, IRQ sharing disabled
serial8250: ttyS0 at MMIO 0x8610e00 (irq = 15) is a TI-AR7
console [ttyS0] enabled, bootconsole disabled
serial8250: ttyS1 at MMIO 0x8610f00 (irq = 16) is a TI-AR7
physmap platform flash device: 00800000 at 10000000
physmap-flash.0: Found 1 x16 devices at 0x0 in 16-bit bank
physmap-flash.0: Found an alias at 0x400000 for the chip at 0x0
 CFI mfr 0x00000001
 CFI id  0x000022f9
 Amd/Fujitsu Extended Query Table at 0x0040
  Amd/Fujitsu Extended Query version 1.1.
number of CFI chips: 1
cfi_cmdset_0002: Disabling erase-suspend-program due to code brokenness.
cmdlinepart partition parsing not available
RedBoot partition parsing not available
4 ar7part partitions found on MTD device physmap-flash.0
Creating 4 MTD partitions on "physmap-flash.0":
0x000000000000-0x000000010000 : "loader"
0x0000003f0000-0x000000400000 : "config"
0x000000010000-0x0000003f0000 : "linux"
0x0000000f0000-0x0000003f0000 : "rootfs"
mtd: partition "rootfs" set to be root filesystem
mtd: partition "rootfs_data" created automatically, ofs=2B0000, len=140000 
0x0000002b0000-0x0000003f0000 : "rootfs_data"
Fixed MDIO Bus: probed
cpmac-mii: probed
cpmac: device eth0 (regs: 08612800, irq: 41, phy: 0:01, mac: 00:15:e9:84:00:00)
cpmac: device eth1 (regs: 08610000, irq: 27, phy: 0:00, mac: 00:15:e9:84:00:00)
Registered led device: status
vlynq0: regs 0x08611800, irq 29, mem 0x04000000
vlynq1: regs 0x08611c00, irq 33, mem 0x0c000000
TCP westwood registered
NET: Registered protocol family 17
802.1Q VLAN Support v1.8 Ben Greear <greearb@candelatech.com>
All bugs added by David S. Miller <davem@redhat.com>
VFS: Mounted root (squashfs filesystem) readonly on device 31:3.
Freeing unused kernel memory: 136k freed
Please be patient, while OpenWrt loads ...
mini_fo: using base directory: /
mini_fo: using storage directory: /tmp/root
device eth0 entered promiscuous mode
PHY: 0:01 - Link is Up - 100/Full
br-lan: port 1(eth0) entering forwarding state
PHY: 0:00 - Link is Up - 100/Full
device eth1 entered promiscuous mode
br-lan: port 2(eth1) entering forwarding state
NET: Registered protocol family 8
NET: Registered protocol family 20
PPP generic driver version 2.4.2
ip_tables: (C) 2000-2006 Netfilter Core Team
NET: Registered protocol family 24
nf_conntrack version 0.5.0 (195 buckets, 780 max)
CONFIG_NF_CT_ACCT is deprecated and will be removed soon. Please use
nf_conntrack.acct=1 kernel parameter, acct=1 nf_conntrack module option or
sysctl net.netfilter.nf_conntrack_acct=1 to enable it.
acx: this driver is still EXPERIMENTAL
acx: reading README file and/or Craig's HOWTO is recommended, visit http://acx100.sf.net in case of further questions/discussion
acx: compiled to use 32bit I/O access. I/O timing issues might occur, such as non-working firmware upload. Report them
acx: running on a little-endian CPU
acx: PCI/VLYNQ module v0.3.37 initialized, waiting for cards to probe...
Not using the 00000009 VLYNQ device's driver for VLYNQ device: 00000000
Not using the 00000029 VLYNQ device's driver for VLYNQ device: 00000000
Not using the 00000009 VLYNQ device's driver for VLYNQ device: 00000000
Not using the 00000029 VLYNQ device's driver for VLYNQ device: 00000000
registered device TI Avalanche SAR
Sangam detected
requesting firmware image "ar0700xx.bin"
 avsar: firmware: requesting ar0700xx.bin
avsar firmware released
tn7dsl_set_modulation : Setting mode to 0xffff
Creating new root folder avalanche in the proc for the driver stats 
Texas Instruments ATM driver: version:[]
jffs2_scan_eraseblock(): End of filesystem marker found at 0x0
jffs2_build_filesystem(): unlocking the mtd device... done.
jffs2_build_filesystem(): erasing all blocks after the end marker... done.
mini_fo: using base directory: /
mini_fo: using storage directory: /overlay
eth0: rx dma ring overrun
eth0: rx dma ring overrun
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  • Last modified: 2019/08/19 17:07
  • by tmomas