It's MT7620A + MT7610E
while 5Ghz's legel TXpower limit is 20dbm, but openwrt doesn't accept anything higher then 11dbm which it super weak. It doesn't to this in stock firmware. as mt7610e support for openwrt is new thing I think this may be a bug.
Can you paste output from dmesg
[ 0.000000] Linux version 4.14.90 (abnoeh@DESKTOP-MAIN) (gcc version 7.4.0 (OpenWrt GCC 7.4.0 r8875-a28f6ab27f)) #0 Tue Dec 25 14:52:37 2018
[ 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 MT7620A ver:2 eco:6
[ 0.000000] bootconsole [early0] enabled
[ 0.000000] CPU0 revision is: 00019650 (MIPS 24KEc)
[ 0.000000] MIPS: machine is TP-Link Archer C2 v1
[ 0.000000] Determined physical RAM map:
[ 0.000000] memory: 04000000 @ 00000000 (usable)
[ 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] free_area_init_node: node 0, pgdat 80491920, node_mem_map 81000040
[ 0.000000] Normal zone: 128 pages used for memmap
[ 0.000000] Normal zone: 0 pages reserved
[ 0.000000] Normal zone: 16384 pages, LIFO batch:3
[ 0.000000] random: get_random_bytes called from start_kernel+0x8c/0x474 with crng_init=0
[ 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: 16256
[ 0.000000] Kernel command line: console=ttyS0,115200 rootfstype=squashfs,jffs2
[ 0.000000] PID hash table entries: 256 (order: -2, 1024 bytes)
[ 0.000000] Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
[ 0.000000] Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.000000] Writing ErrCtl register=0007f270
[ 0.000000] Readback ErrCtl register=0007f270
[ 0.000000] Memory: 59788K/65536K available (3653K kernel code, 175K rwdata, 852K rodata, 176K init, 208K bss, 5748K 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] CPU Clock: 580MHz
[ 0.000000] clocksource: systick: mask: 0xffff max_cycles: 0xffff, max_idle_ns: 583261500 ns
[ 0.000000] systick: enable autosleep mode
[ 0.000000] systick: running - mult: 214748, shift: 32
[ 0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 6590553264 ns
[ 0.000011] sched_clock: 32 bits at 290MHz, resolution 3ns, wraps every 7405115902ns
[ 0.007588] Calibrating delay loop... 385.84 BogoMIPS (lpj=1929216)
[ 0.073550] pid_max: default: 32768 minimum: 301
[ 0.078258] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.084637] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.097955] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.107495] futex hash table entries: 256 (order: -1, 3072 bytes)
[ 0.113486] pinctrl core: initialized pinctrl subsystem
[ 0.119078] NET: Registered protocol family 16
[ 0.385255] PCI host bridge /pcie@10140000 ranges:
[ 0.389872] MEM 0x0000000020000000..0x000000002fffffff
[ 0.394920] IO 0x0000000010160000..0x000000001016ffff
[ 0.418010] rt2880_gpio 10000600.gpio: registering 24 gpios
[ 0.423468] rt2880_gpio 10000600.gpio: registering 24 irq handlers
[ 0.429797] rt2880_gpio 10000638.gpio: registering 16 gpios
[ 0.435222] rt2880_gpio 10000638.gpio: registering 16 irq handlers
[ 0.441520] rt2880_gpio 10000660.gpio: registering 32 gpios
[ 0.446943] rt2880_gpio 10000660.gpio: registering 32 irq handlers
[ 0.453238] rt2880_gpio 10000688.gpio: registering 1 gpios
[ 0.458575] rt2880_gpio 10000688.gpio: registering 1 irq handlers
[ 0.465285] PCI host bridge to bus 0000:00
[ 0.469263] pci_bus 0000:00: root bus resource [mem 0x20000000-0x2fffffff]
[ 0.475878] pci_bus 0000:00: root bus resource [io 0xffffffff]
[ 0.481637] pci_bus 0000:00: root bus resource [??? 0x00000000 flags 0x0]
[ 0.488220] pci_bus 0000:00: No busn resource found for root bus, will use [bus 00-ff]
[ 0.495963] pci 0000:00:00.0: [1814:0801] type 01 class 0x060400
[ 0.496005] pci 0000:00:00.0: reg 0x10: [mem 0x00000000-0x7fffffff]
[ 0.496021] pci 0000:00:00.0: reg 0x14: [mem 0x20200000-0x2020ffff]
[ 0.496114] pci 0000:00:00.0: supports D1
[ 0.496125] pci 0000:00:00.0: PME# supported from D0 D1 D3hot
[ 0.496583] pci 0000:01:00.0: [14c3:7650] type 00 class 0x028000
[ 0.496633] pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x000fffff]
[ 0.496779] pci 0000:01:00.0: PME# supported from D0 D3hot D3cold
[ 0.497038] pci 0000:01:00.1: [14c3:8650] type 00 class 0x0d1100
[ 0.497087] pci 0000:01:00.1: reg 0x10: [mem 0x00000000-0x000fffff]
[ 0.497224] pci 0000:01:00.1: supports D1
[ 0.497234] pci 0000:01:00.1: PME# supported from D0 D1 D3hot D3cold
[ 0.497453] pci_bus 0000:01: busn_res: [bus 01-ff] end is updated to 01
[ 0.497472] pci_bus 0000:00: busn_res: [bus 00-ff] end is updated to 01
[ 0.497524] pci 0000:00:00.0: BAR 0: no space for [mem size 0x80000000]
[ 0.503889] pci 0000:00:00.0: BAR 0: failed to assign [mem size 0x80000000]
[ 0.510706] pci 0000:00:00.0: BAR 8: assigned [mem 0x20000000-0x201fffff]
[ 0.517244] pci 0000:00:00.0: BAR 1: assigned [mem 0x20200000-0x2020ffff]
[ 0.523860] pci 0000:01:00.0: BAR 0: assigned [mem 0x20000000-0x200fffff]
[ 0.530433] pci 0000:01:00.1: BAR 0: assigned [mem 0x20100000-0x201fffff]
[ 0.537039] pci 0000:00:00.0: PCI bridge to [bus 01]
[ 0.541842] pci 0000:00:00.0: bridge window [mem 0x20000000-0x201fffff]
[ 0.553731] clocksource: Switched to clocksource systick
[ 0.560095] NET: Registered protocol family 2
[ 0.565162] TCP established hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.571885] TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.578114] TCP: Hash tables configured (established 1024 bind 1024)
[ 0.584394] UDP hash table entries: 256 (order: 0, 4096 bytes)
[ 0.590023] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
[ 0.596403] NET: Registered protocol family 1
[ 0.600639] PCI: CLS 0 bytes, default 32
[ 0.603389] rt-timer 10000100.timer: maximum frequency is 1220Hz
[ 0.610133] Crashlog allocated RAM at address 0x3f00000
[ 0.616936] workingset: timestamp_bits=30 max_order=14 bucket_order=0
[ 0.628838] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 0.634490] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
[ 0.654196] io scheduler noop registered
[ 0.657945] io scheduler deadline registered (default)
[ 0.663960] Serial: 8250/16550 driver, 2 ports, IRQ sharing disabled
[ 0.671191] console [ttyS0] disabled
[ 0.674704] 10000c00.uartlite: ttyS0 at MMIO 0x10000c00 (irq = 20, base_baud = 2500000) is a Palmchip BK-3103
[ 0.684318] console [ttyS0] enabled
[ 0.691359] bootconsole [early0] disabled
[ 0.700098] cacheinfo: Failed to find cpu0 device node
[ 0.705388] cacheinfo: Unable to detect cache hierarchy for CPU 0
[ 0.716458] spi spi0.0: force spi mode3
[ 0.732673] m25p80 spi0.0: s25fl064k (8192 Kbytes)
[ 0.737641] 6 fixed-partitions partitions found on MTD device spi0.0
[ 0.744137] Creating 6 MTD partitions on "spi0.0":
[ 0.749051] 0x000000000000-0x000000020000 : "u-boot"
[ 0.755057] 0x000000020000-0x0000007c0000 : "firmware"
[ 0.763573] 2 tplink-fw partitions found on MTD device firmware
[ 0.769688] Creating 2 MTD partitions on "firmware":
[ 0.774779] 0x000000000000-0x0000001807b0 : "kernel"
[ 0.780815] 0x0000001807b0-0x0000007a0000 : "rootfs"
[ 0.786729] mtd: device 3 (rootfs) set to be root filesystem
[ 0.794188] 1 squashfs-split partitions found on MTD device rootfs
[ 0.800519] 0x000000557000-0x0000007a0000 : "rootfs_data"
[ 0.806979] 0x0000007c0000-0x0000007d0000 : "config"
[ 0.812873] 0x0000007d0000-0x0000007e0000 : "rom"
[ 0.818614] 0x0000007e0000-0x0000007f0000 : "romfile"
[ 0.824711] 0x0000007f0000-0x000000800000 : "radio"
[ 0.831308] libphy: Fixed MDIO Bus: probed
[ 0.846850] gsw: setting port4 to ephy mode
[ 0.851444] libphy: mdio: probed
[ 0.854836] mtk_soc_eth 10100000.ethernet: using fixed link parameters
[ 0.861567] mtk_soc_eth 10100000.ethernet: loaded mt7620 driver
[ 0.868302] mtk_soc_eth 10100000.ethernet eth0: mediatek frame engine at 0xb0100000, irq 5
[ 0.877289] rt2880_wdt 10000120.watchdog: Initialized
[ 0.883807] NET: Registered protocol family 10
[ 0.892202] Segment Routing with IPv6
[ 0.896130] NET: Registered protocol family 17
[ 0.900721] 8021q: 802.1Q VLAN Support v1.8
[ 0.917415] VFS: Mounted root (squashfs filesystem) readonly on device 31:3.
[ 0.925634] Freeing unused kernel memory: 176K
[ 0.930168] This architecture does not have kernel memory protection.
[ 2.523681] random: fast init done
[ 2.676014] init: Console is alive
[ 2.679754] init: - watchdog -
[ 5.936613] kmodloader: loading kernel modules from /etc/modules-boot.d/*
[ 6.273773] usbcore: registered new interface driver usbfs
[ 6.279464] usbcore: registered new interface driver hub
[ 6.285032] usbcore: registered new device driver usb
[ 6.341451] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 6.357748] SCSI subsystem initialized
[ 6.367182] ehci-platform: EHCI generic platform driver
[ 6.382913] phy phy-usbphy.0: remote usb device wakeup disabled
[ 6.388974] phy phy-usbphy.0: UTMI 16bit 30MHz
[ 6.393524] ehci-platform 101c0000.ehci: EHCI Host Controller
[ 6.399432] ehci-platform 101c0000.ehci: new USB bus registered, assigned bus number 1
[ 6.407662] ehci-platform 101c0000.ehci: irq 26, io mem 0x101c0000
[ 6.424372] ehci-platform 101c0000.ehci: USB 2.0 started, EHCI 1.00
[ 6.431797] hub 1-0:1.0: USB hub found
[ 6.436110] hub 1-0:1.0: 1 port detected
[ 6.443684] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[ 6.451819] ohci-platform: OHCI generic platform driver
[ 6.457516] ohci-platform 101c1000.ohci: Generic Platform OHCI controller
[ 6.464512] ohci-platform 101c1000.ohci: new USB bus registered, assigned bus number 2
[ 6.472695] ohci-platform 101c1000.ohci: irq 26, io mem 0x101c1000
[ 6.506296] hub 2-0:1.0: USB hub found
[ 6.510595] hub 2-0:1.0: 1 port detected
[ 6.523450] usbcore: registered new interface driver usb-storage
[ 6.530262] kmodloader: done loading kernel modules from /etc/modules-boot.d/*
[ 6.541804] init: - preinit -
[ 7.364942] usb 1-1: new high-speed USB device number 2 using ehci-platform
[ 7.675312] random: procd: uninitialized urandom read (4 bytes read)
[ 7.682752] usb-storage 1-1:1.0: USB Mass Storage device detected
[ 7.701642] scsi host0: usb-storage 1-1:1.0
[ 8.097036] mtk_soc_eth 10100000.ethernet eth0: port 5 link up (1000Mbps/Full duplex)
[ 8.105814] 8021q: adding VLAN 0 to HW filter on device eth0
[ 8.708528] scsi 0:0:0:0: Direct-Access General USB Flash Disk 1100 PQ: 0 ANSI: 4
[ 8.719888] sd 0:0:0:0: [sda] 31506432 512-byte logical blocks: (16.1 GB/15.0 GiB)
[ 8.728276] sd 0:0:0:0: [sda] Write Protect is off
[ 8.733185] sd 0:0:0:0: [sda] Mode Sense: 43 00 00 00
[ 8.733627] sd 0:0:0:0: [sda] No Caching mode page found
[ 8.739123] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 8.757082] sda: sda1
[ 8.762597] sd 0:0:0:0: [sda] Attached SCSI removable disk
[ 9.439307] mount_root: loading kmods from internal overlay
[ 9.482372] kmodloader: loading kernel modules from //etc/modules-boot.d/*
[ 9.491220] kmodloader: done loading kernel modules from //etc/modules-boot.d/*
[ 12.133138] jffs2: notice: (459) jffs2_build_xattr_subsystem: complete building xattr subsystem, 3 of xdatum (2 unchecked, 1 orphan) and 11 of xref (1 dead, 0 orphan) found.
[ 12.149979] block: attempting to load /tmp/jffs_cfg/upper/etc/config/fstab
[ 12.385354] F2FS-fs (sda1): Mounted with checkpoint version = 15096a30
[ 12.433441] mount_root: switched to extroot
[ 12.441824] urandom-seed: Seeding with /etc/urandom.seed
[ 12.532640] mtk_soc_eth 10100000.ethernet eth0: port 5 link down
[ 12.551077] procd: - early -
[ 12.554213] procd: - watchdog -
[ 13.054707] procd: - watchdog -
[ 13.058240] procd: - ubus -
[ 13.385810] random: ubusd: uninitialized urandom read (4 bytes read)
[ 13.672448] random: ubusd: uninitialized urandom read (4 bytes read)
[ 13.680438] random: ubusd: uninitialized urandom read (4 bytes read)
[ 13.688866] procd: - init -
[ 14.487907] kmodloader: loading kernel modules from /etc/modules.d/*
[ 14.502172] urandom_read: 5 callbacks suppressed
[ 14.502182] random: ubusd: uninitialized urandom read (4 bytes read)
[ 14.523638] ip6_tables: (C) 2000-2006 Netfilter Core Team
[ 14.557143] rtl8367b rtl8367rb: using MDIO bus 'mdio'
[ 14.563252] rtl8367b rtl8367rb: RTL8367RB chip found
[ 15.839479] libphy: rtl8367rb: probed
[ 15.851409] Loading modules backported from Linux version v4.19.7-0-g61c68f2a2af0
[ 15.859118] Backport generated by backports.git v4.19.7-1-0-g148b072d
[ 15.870499] ip_tables: (C) 2000-2006 Netfilter Core Team
[ 15.887394] nf_conntrack version 0.5.0 (1024 buckets, 4096 max)
[ 15.972978] xt_time: kernel timezone is -0000
[ 16.056509] PPP generic driver version 2.4.2
[ 16.067703] NET: Registered protocol family 24
[ 16.089925] mt76x0e 0000:01:00.0: card - bus=0x1, slot = 0x0 irq=4
[ 16.096415] mt76x0e 0000:01:00.0: ASIC revision: 76100002
[ 16.104401] mt76x0e 0000:01:00.0: Firmware Version: 0.1.00
[ 16.194651] mt76x0e 0000:01:00.0: EEPROM ver:02 fae:00
[ 16.203921] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'
[ 16.310629] rt2800_wmac 10180000.wmac: loaded eeprom from mtd device "radio"
[ 16.317903] ieee80211 phy1: rt2x00_set_rt: Info - RT chipset 6352, rev 0500 detected
[ 16.325966] ieee80211 phy1: rt2x00_set_rf: Info - RF chipset 7620 detected
[ 16.333690] ieee80211 phy1: Selected rate control algorithm 'minstrel_ht'
[ 16.339442] kmodloader: done loading kernel modules from /etc/modules.d/*
[ 27.914340] mtk_soc_eth 10100000.ethernet eth0: port 5 link up (1000Mbps/Full duplex)
[ 27.923147] 8021q: adding VLAN 0 to HW filter on device eth0
[ 27.962113] br-lan: port 1(eth0.1) entered blocking state
[ 27.967639] br-lan: port 1(eth0.1) entered disabled state
[ 27.973597] device eth0.1 entered promiscuous mode
[ 27.978493] device eth0 entered promiscuous mode
[ 28.201519] br-lan: port 1(eth0.1) entered blocking state
[ 28.207047] br-lan: port 1(eth0.1) entered forwarding state
[ 28.212983] IPv6: ADDRCONF(NETDEV_UP): br-lan: link is not ready
[ 28.921939] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
[ 34.703801] ieee80211 phy1: rt2800_rf_self_txdc_cal: Info - RF Tx self calibration start
[ 34.712616] ieee80211 phy1: rt2800_rf_self_txdc_cal: Info - RF Tx self calibration end
[ 37.629481] ieee80211 phy1: rt2800_loft_iq_calibration: Info - LOFT Calibration Done!
[ 37.641140] ieee80211 phy1: rt2800_iq_search: Info - IQCalibration Start!
[ 37.662548] ieee80211 phy1: rt2800_iq_search: Info - IQCalibration Done! CH = 0, (gain= 3, phase=3c)
[ 37.672807] ieee80211 phy1: rt2800_iq_search: Info - IQCalibration Start!
[ 37.694119] ieee80211 phy1: rt2800_iq_search: Info - IQCalibration Done! CH = 1, (gain= 0, phase= 1)
[ 37.703476] ieee80211 phy1: rt2800_loft_iq_calibration: Info - TX IQ Calibration Done!
[ 37.742262] ieee80211 phy1: rt2800_rxiq_calibration: Info - RXIQ G_imb=-1, Ph_rx=-5
[ 37.762777] ieee80211 phy1: rt2800_rxiq_calibration: Info - RXIQ G_imb=1, Ph_rx=-1
[ 37.780623] IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready
[ 37.913783] br-lan: port 2(wlan1) entered blocking state
[ 37.919220] br-lan: port 2(wlan1) entered disabled state
[ 37.925113] device wlan1 entered promiscuous mode
[ 39.406674] IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
[ 39.413440] br-lan: port 2(wlan1) entered blocking state
[ 39.418916] br-lan: port 2(wlan1) entered forwarding state
[ 39.597844] random: crng init done
[ 168.857325] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 168.868879] br-lan: port 3(wlan0) entered blocking state
[ 168.874317] br-lan: port 3(wlan0) entered disabled state
[ 168.880218] device wlan0 entered promiscuous mode
[ 179.122531] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[ 179.129444] br-lan: port 3(wlan0) entered blocking state
[ 179.134953] br-lan: port 3(wlan0) entered forwarding state
and there is
hostapd: ACS: Survey is missing noise floor
log spam in system log (in luci)
Any solutions already? - I found a lot of solutions in patching, but no ready-made package for openwrt or implementation in linux-kernel.