[OpenWrt Wiki] TP-Link Archer C20 (EU) V5 (2024)

→ Install OpenWrt (generic explanation)

As all installation methods require a U-Boot to be integrated into the Image (and we do not ship one with the image) we are not able to create an image in the OpenWrt build-process.

Download a TP-Link image from their Website(pay attention to regional match, i.e. if the router is EU-based, download firmware file for EU) and a OpenWrt sysupgrade image for the device and build yourself a factory image like following:

TP-Link image: tpl.binOpenWrt sysupgrade image: owrt.bin > dd if=tpl.bin of=boot.bin bs=131584 count=1 > cat owrt.bin >> boot.bin

Activate Web-Recovery by beginning the upgrade Process with a Firmware-Image from TP-Link. After starting the Firmware Upgrade, wait ~3 seconds (When update status is switching to 0%), then disconnect the power supply from the device. Upgrade flag (which activates Web-Recovery) is written before the OS-image is touched and removed after write is succesful, so this procedure should be safe.

Plug the power back in. It will come up in Recovery-Mode on 192.168.0.1. When active, all LEDs but the WPS LED are off. Remeber to assign yourself a static IP-address as DHCP is not active in this mode.

The boot.bin can now be uploaded and flashed using the web-recovery.

Prepare an image like following (Filenames from factory image steps apply here)

 > dd if=/dev/zero of=tp_recovery.bin bs=196608 count=1 > dd if=tpl.bin of=tmp.bin bs=131584 count=1 > dd if=tmp.bin of=boot.bin bs=512 skip=1 > cat boot.bin >> tp_recovery.bin > cat owrt.bin >> tp_recovery.bin

Place tp_recovery.bin in root directory of TFTP server and listen on 192.168.0.66/24.

Connect router LAN ports with your computer and power up the router while pressing the reset button. The router will download the image via tftp and after ~1 Minute reboot into OpenWrt.

TP-Link integrated a new Web-Recovery like the one on the Archer C7v4 / TL-WR1043v5 / Archer C50v4. Stock-firmware sets a flag in the “romfile” partition before beginning to write and removes it afterwards. If the router boots with this flag set, bootloader will automatically startWeb-recovery and listens on 192.168.0.1. This way, the vendor-firmware or an OpenWrt factory image can be written.

By doing the same while performing sysupgrade, we can take advantage of the Web-recovery in OpenWrt.

It is important to note that Web-Recovery is only based on this flag. It can't detect e.g. a crashing kernel or other means. Once activated itwon't boot the OS before a recovery action (either via TFTP or HTTP) is performed. This recovery-mode is indicated by an illuminated WPS-LED onboot.

→ hotplug_lede on howto use and configure the hardware button(s).Here, we merely name the buttons, so we can use them in the above Howto.

The TP-Link Archer C20(EU) v5 has the following buttons:

https://postimg.cc/gallery/XbQdBx6

→ port.serial general information about the serial port, serial port cable, etc.

There should be 4 pads (J1) looking from the font on right side, where pin 1 (marked with silk-screen both with a thicker line and with a triangle) is TX.

FRONT | TX - RX - GND - VCC | BACK

... TBD ...

[ 0.000000] Linux version 5.4.179 (builder@buildhost) (gcc version 8.4.0 (OpenWrt GCC 8.4.0 r16495-bf0c965af0)) #0 Wed Feb 16 20:29:10 2022[ 0.000000] Board has DDR2[ 0.000000] Analog PMU set to hw control[ 0.000000] Digital PMU set to hw control[ 0.000000] SoC Type: MediaTek MT7628AN ver:1 eco:2[ 0.000000] printk: bootconsole [early0] enabled[ 0.000000] CPU0 revision is: 00019655 (MIPS 24KEc)[ 0.000000] MIPS: machine is TP-Link Archer C20 v5[ 0.000000] Initrd not found or empty - disabling initrd[ 0.000000] Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.[ 0.000000] Primary data cache 32kB, 4-way, PIPT, no aliases, linesize 32 bytes[ 0.000000] Zone ranges:[ 0.000000] Normal [mem 0x0000000000000000-0x0000000003ffffff][ 0.000000] Movable zone start for each node[ 0.000000] Early memory node ranges[ 0.000000] node 0: [mem 0x0000000000000000-0x0000000003ffffff][ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x0000000003ffffff][ 0.000000] On node 0 totalpages: 16384[ 0.000000] Normal zone: 144 pages used for memmap[ 0.000000] Normal zone: 0 pages reserved[ 0.000000] Normal zone: 16384 pages, LIFO batch:3[ 0.000000] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768[ 0.000000] pcpu-alloc: [0] 0 [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 16240[ 0.000000] Kernel command line: console=ttyS0,115200 rootfstype=squashfs,jffs2[ 0.000000] Dentry cache hash table entries: 8192 (order: 3, 32768 bytes, linear)[ 0.000000] Inode-cache hash table entries: 4096 (order: 2, 16384 bytes, linear)[ 0.000000] Writing ErrCtl register=0002f819[ 0.000000] Readback ErrCtl register=0002f819[ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off[ 0.000000] Memory: 57444K/65536K available (5093K kernel code, 208K rwdata, 636K rodata, 1220K init, 205K bss, 8092K reserved, 0K cma-reserved)[ 0.000000] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1[ 0.000000] NR_IRQS: 256[ 0.000000] intc: using register map from devicetree[ 0.000000] random: get_random_bytes called from 0x805cfa28 with crng_init=0[ 0.000000] CPU Clock: 580MHz[ 0.000000] timer_probe: no matching timers found[ 0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 6590553264 ns[ 0.000009] sched_clock: 32 bits at 290MHz, resolution 3ns, wraps every 7405115902ns[ 0.007574] Calibrating delay loop... 385.02 BogoMIPS (lpj=770048)[ 0.045464] pid_max: default: 32768 minimum: 301[ 0.050104] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)[ 0.057123] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)[ 0.070539] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns[ 0.079963] futex hash table entries: 256 (order: -1, 3072 bytes, linear)[ 0.086612] pinctrl core: initialized pinctrl subsystem[ 0.094549] NET: Registered protocol family 16[ 0.203310] mt7620-pci 10140000.pcie: Port 0 N_FTS = 1b105000[ 0.358414] PCI host bridge /pcie@10140000 ranges:[ 0.362994] MEM 0x0000000020000000..0x000000002fffffff[ 0.368022] IO 0x0000000010160000..0x000000001016ffff[ 0.394884] PCI host bridge to bus 0000:00[ 0.398864] pci_bus 0000:00: root bus resource [mem 0x20000000-0x2fffffff][ 0.405463] pci_bus 0000:00: root bus resource [io 0x10160000-0x1016ffff][ 0.412090] pci_bus 0000:00: root bus resource [??? 0x00000000 flags 0x0][ 0.418639] pci_bus 0000:00: No busn resource found for root bus, will use [bus 00-ff][ 0.426337] pci 0000:00:00.0: [14c3:0801] type 01 class 0x060400[ 0.432120] pci 0000:00:00.0: reg 0x10: [mem 0x00000000-0x7fffffff][ 0.438138] pci 0000:00:00.0: reg 0x14: [mem 0x00000000-0x0000ffff][ 0.444256] pci 0000:00:00.0: supports D1[ 0.448060] pci 0000:00:00.0: PME# supported from D0 D1 D3hot[ 0.455304] pci 0000:00:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring[ 0.463213] pci 0000:01:00.0: [14c3:7650] type 00 class 0x028000[ 0.469033] pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x000fffff][ 0.475184] pci 0000:01:00.0: PME# supported from D0 D3hot D3cold[ 0.481291] pci 0000:01:00.1: [14c3:8650] type 00 class 0x0d1100[ 0.487110] pci 0000:01:00.1: reg 0x10: [mem 0x00000000-0x000fffff][ 0.493249] pci 0000:01:00.1: supports D1[ 0.497052] pci 0000:01:00.1: PME# supported from D0 D1 D3hot D3cold[ 0.504836] pci_bus 0000:01: busn_res: [bus 01-ff] end is updated to 01[ 0.511211] pci_bus 0000:00: busn_res: [bus 00-ff] end is updated to 01[ 0.517598] pci 0000:00:00.0: BAR 0: no space for [mem size 0x80000000][ 0.523946] pci 0000:00:00.0: BAR 0: failed to assign [mem size 0x80000000][ 0.530667] pci 0000:00:00.0: BAR 8: assigned [mem 0x20000000-0x201fffff][ 0.537220] pci 0000:00:00.0: BAR 1: assigned [mem 0x20200000-0x2020ffff][ 0.543784] pci 0000:01:00.0: BAR 0: assigned [mem 0x20000000-0x200fffff][ 0.550328] pci 0000:01:00.1: BAR 0: assigned [mem 0x20100000-0x201fffff][ 0.556878] pci 0000:00:00.0: PCI bridge to [bus 01][ 0.561664] pci 0000:00:00.0: bridge window [mem 0x20000000-0x201fffff][ 0.572862] clocksource: Switched to clocksource MIPS[ 0.578791] thermal_sys: Registered thermal governor 'step_wise'[ 0.579192] NET: Registered protocol family 2[ 0.589336] IP idents hash table entries: 2048 (order: 2, 16384 bytes, linear)[ 0.597227] tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 4096 bytes, linear)[ 0.605327] TCP established hash table entries: 1024 (order: 0, 4096 bytes, linear)[ 0.612698] TCP bind hash table entries: 1024 (order: 0, 4096 bytes, linear)[ 0.619496] TCP: Hash tables configured (established 1024 bind 1024)[ 0.625772] UDP hash table entries: 256 (order: 0, 4096 bytes, linear)[ 0.632092] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes, linear)[ 0.639086] NET: Registered protocol family 1[ 0.643355] PCI: CLS 0 bytes, default 32[ 0.651851] workingset: timestamp_bits=14 max_order=14 bucket_order=0[ 0.666099] squashfs: version 4.0 (2009/01/31) Phillip Lougher[ 0.671735] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.[ 0.696673] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)[ 0.707121] mt7621_gpio 10000600.gpio: registering 32 gpios[ 0.712802] mt7621_gpio 10000600.gpio: registering 32 gpios[ 0.718453] mt7621_gpio 10000600.gpio: registering 32 gpios[ 0.724150] Serial: 8250/16550 driver, 16 ports, IRQ sharing enabled[ 0.733119] printk: console [ttyS0] disabled[ 0.737281] 10000c00.uartlite: ttyS0 at MMIO 0x10000c00 (irq = 28, base_baud = 2500000) is a 16550A[ 0.746014] printk: console [ttyS0] enabled[ 0.754421] printk: bootconsole [early0] disabled[ 0.765355] spi-mt7621 10000b00.spi: sys_freq: 193333333[ 0.780442] spi-nor spi0.0: en25qh64 (8192 Kbytes)[ 0.785448] 7 fixed-partitions partitions found on MTD device spi0.0[ 0.791914] Creating 7 MTD partitions on "spi0.0":[ 0.796799] 0x000000000000-0x000000030000 : "factory-uboot"[ 0.803579] 0x000000030000-0x000000050000 : "boot"[ 0.809630] 0x000000050000-0x0000007c0000 : "firmware"[ 0.819583] 2 tplink-fw partitions found on MTD device firmware[ 0.825667] Creating 2 MTD partitions on "firmware":[ 0.830731] 0x000000000000-0x0000001e89d1 : "kernel"[ 0.836932] 0x0000001e89d4-0x000000770000 : "rootfs"[ 0.842958] mtd: device 4 (rootfs) set to be root filesystem[ 0.850856] 1 squashfs-split partitions found on MTD device rootfs[ 0.857220] 0x000000500000-0x000000770000 : "rootfs_data"[ 0.863839] 0x0000007c0000-0x0000007d0000 : "config"[ 0.870009] 0x0000007d0000-0x0000007e0000 : "rom"[ 0.875897] 0x0000007e0000-0x0000007f0000 : "romfile"[ 0.882132] 0x0000007f0000-0x000000800000 : "radio"[ 0.904008] rt3050-esw 10110000.esw: link changed 0x00[ 0.911242] mtk_soc_eth 10100000.ethernet eth0: mediatek frame engine at 0xb0100000, irq 5[ 0.921772] NET: Registered protocol family 10[ 0.930815] Segment Routing with IPv6[ 0.934742] NET: Registered protocol family 17[ 0.939353] bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.[ 0.952517] 8021q: 802.1Q VLAN Support v1.8[ 0.966970] VFS: Mounted root (squashfs filesystem) readonly on device 31:4.[ 0.981056] Freeing unused kernel memory: 1220K[ 0.985682] This architecture does not have kernel memory protection.[ 0.992223] Run /sbin/init as init process[ 1.204862] random: fast init done[ 1.904086] init: Console is alive[ 1.907963] init: - watchdog -[ 2.981531] kmodloader: loading kernel modules from /etc/modules-boot.d/*[ 3.152634] kmodloader: done loading kernel modules from /etc/modules-boot.d/*[ 3.170563] init: - preinit -[ 4.850200] random: jshn: uninitialized urandom read (4 bytes read)[ 4.942469] random: jshn: uninitialized urandom read (4 bytes read)[ 5.171452] random: jshn: uninitialized urandom read (4 bytes read)[ 5.739688] rt3050-esw 10110000.esw: link changed 0x00[ 5.945307] urandom_read: 2 callbacks suppressed[ 5.945317] random: procd: uninitialized urandom read (4 bytes read)[ 9.309710] rt3050-esw 10110000.esw: link changed 0x01[ 10.180196] jffs2: notice: (470) jffs2_build_xattr_subsystem: complete building xattr subsystem, 9 of xdatum (0 unchecked, 1 orphan) and 10 of xref (1 dead, 0 orphan) found.[ 10.198031] mount_root: switching to jffs2 overlay[ 10.210143] overlayfs: upper fs does not support tmpfile.[ 10.223268] urandom-seed: Seeding with /etc/urandom.seed[ 10.349228] procd: - early -[ 10.352265] procd: - watchdog -[ 10.962564] procd: - watchdog -[ 10.967648] procd: - ubus -[ 11.039929] random: ubusd: uninitialized urandom read (4 bytes read)[ 11.049153] random: ubusd: uninitialized urandom read (4 bytes read)[ 11.056278] random: ubusd: uninitialized urandom read (4 bytes read)[ 11.066185] procd: - init -[ 12.216382] kmodloader: loading kernel modules from /etc/modules.d/*[ 12.262412] Loading modules backported from Linux version v5.10.85-0-ge4f2aee6612e[ 12.270193] Backport generated by backports.git v5.10.85-1-0-gf988973f[ 12.337773] xt_time: kernel timezone is -0000[ 12.456816] mt76_wmac 10300000.wmac: ASIC revision: 76280001[ 12.616190] urngd: v1.0.2 started.[ 12.825370] crng init done[ 12.828121] random: 1 urandom warning(s) missed due to ratelimiting[ 13.506773] mt76_wmac 10300000.wmac: Firmware Version: 20151201[ 13.512879] mt76_wmac 10300000.wmac: Build Time: 20151201183641[ 13.552878] mt76_wmac 10300000.wmac: firmware init done[ 13.729561] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'[ 13.852327] PPP generic driver version 2.4.2[ 13.865731] NET: Registered protocol family 24[ 13.910213] mt76x0e 0000:01:00.0: card - bus=0x1, slot = 0x0 irq=4[ 13.916774] mt76x0e 0000:01:00.0: ASIC revision: 76100002[ 14.185585] mt76x0e 0000:01:00.0: Firmware Version: 0.1.00[ 14.466619] mt76x0e 0000:01:00.0: EEPROM ver:02 fae:00[ 14.479599] ieee80211 phy1: Selected rate control algorithm 'minstrel_ht'[ 14.495116] kmodloader: done loading kernel modules from /etc/modules.d/*[ 20.474369] rt3050-esw 10110000.esw: link changed 0x00[ 24.093075] rt3050-esw 10110000.esw: link changed 0x01

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