Tested, and it works! It would be cool to see this patch in the upcoming sources. I'm not a great git specialist, but I think the next git pull will give me a conflict with a manually patched file)
It remains to solve another problem with the Ethernet port, this is more important.
There is dmesg (with patched console speed and 20967 trunk), if it helps:
[ 0.000000] Linux version 5.15.72 (openwrt@build) (mips-openwrt-linux-musl-gcc (OpenWrt GCC 11.3.0 r20877-7d6032f310) 11.3.0, GNU ld (GNU Binutils) 2.37) #0 Tue Oct 18 07:50:05 2022
[ 0.000000] printk: bootconsole [early0] enabled
[ 0.000000] CPU0 revision is: 00019374 (MIPS 24Kc)
[ 0.000000] MIPS: machine is Netgear WNDAP360
[ 0.000000] SoC: Atheros AR7161 rev 2
[ 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, VIPT, cache aliases, linesize 32 bytes
[ 0.000000] Zone ranges:
[ 0.000000] Normal [mem 0x0000000000000000-0x0000000007ffffff]
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000000000000-0x0000000007ffffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x0000000007ffffff]
[ 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: 32480
[ 0.000000] Kernel command line: console=ttyS0,9600 rootfstype=squashfs,jffs2
[ 0.000000] Dentry cache hash table entries: 16384 (order: 4, 65536 bytes, linear)
[ 0.000000] Inode-cache hash table entries: 8192 (order: 3, 32768 bytes, linear)
[ 0.000000] Writing ErrCtl register=00000000
[ 0.000000] Readback ErrCtl register=00000000
[ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[ 0.000000] Memory: 109252K/131072K available (5373K kernel code, 581K rwdata, 1020K rodata, 13304K init, 206K bss, 21820K reserved, 0K cma-reserved)
[ 0.000000] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.000000] NR_IRQS: 51
[ 0.000000] CPU clock: 680.000 MHz
[ 0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 5621354254 ns
[ 0.000002] sched_clock: 32 bits at 340MHz, resolution 2ns, wraps every 6316128254ns
[ 0.092873] Calibrating delay loop... 452.19 BogoMIPS (lpj=2260992)
[ 0.227854] pid_max: default: 32768 minimum: 301
[ 0.283381] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 0.370901] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 0.465732] dyndbg: Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build
[ 0.559765] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.677481] futex hash table entries: 256 (order: -1, 3072 bytes, linear)
[ 0.758849] pinctrl core: initialized pinctrl subsystem
[ 0.822771] NET: Registered PF_NETLINK/PF_ROUTE protocol family
[ 1.206398] PCI host bridge to bus 0000:00
[ 1.255416] pci_bus 0000:00: root bus resource [mem 0x10000000-0x16ffffff]
[ 1.337709] pci_bus 0000:00: root bus resource [io 0x0000]
[ 1.404433] pci_bus 0000:00: No busn resource found for root bus, will use [bus 00-ff]
[ 1.499685] pci 0000:00:11.0: [168c:ff1d] type 00 class 0x020000
[ 1.571625] pci 0000:00:11.0: reg 0x10: [mem 0x00000000-0x0000ffff]
[ 1.646965] pci 0000:00:12.0: [168c:ff1d] type 00 class 0x020000
[ 1.718933] pci 0000:00:12.0: reg 0x10: [mem 0x00000000-0x0000ffff]
[ 1.794484] pci_bus 0000:00: busn_res: [bus 00-ff] end is updated to 00
[ 1.873724] pci 0000:00:11.0: BAR 0: assigned [mem 0x10000000-0x1000ffff]
[ 1.954992] pci 0000:00:12.0: BAR 0: assigned [mem 0x10010000-0x1001ffff]
[ 2.036723] clocksource: Switched to clocksource MIPS
[ 2.098082] NET: Registered PF_INET protocol family
[ 2.156689] IP idents hash table entries: 2048 (order: 2, 16384 bytes, linear)
[ 2.243858] tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 4096 bytes, linear)
[ 2.343945] Table-perturb hash table entries: 65536 (order: 6, 262144 bytes, linear)
[ 2.436656] TCP established hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 2.528357] TCP bind hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 2.612777] TCP: Hash tables configured (established 1024 bind 1024)
[ 2.688987] UDP hash table entries: 256 (order: 0, 4096 bytes, linear)
[ 2.767179] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes, linear)
[ 2.850794] NET: Registered PF_UNIX/PF_LOCAL protocol family
[ 2.918578] PCI: CLS 0 bytes, default 32
[ 3.153090] workingset: timestamp_bits=14 max_order=15 bucket_order=1
[ 3.234860] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 3.304718] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
[ 3.423726] Serial: 8250/16550 driver, 1 ports, IRQ sharing disabled
[ 3.500525] printk: console [ttyS0] disabled
[ 3.551720] 18020000.uart: ttyS0 at MMIO 0x18020000 (irq = 10, base_baud = 10625000) is a 16550A
[ 3.656976] printk: console [ttyS0] enabled
[ 3.757060] printk: bootconsole [early0] disabled
[ 3.880564] spi-nor spi0.0: mx25l6405d (8192 Kbytes)
[ 3.940126] 5 fixed-partitions partitions found on MTD device spi0.0
[ 4.016321] OF: Bad cell count for /spi@1f000000/flash@0/partitions
[ 4.091418] OF: Bad cell count for /spi@1f000000/flash@0/partitions
[ 4.166812] OF: Bad cell count for /spi@1f000000/flash@0/partitions
[ 4.241971] OF: Bad cell count for /spi@1f000000/flash@0/partitions
[ 4.317571] Creating 5 MTD partitions on "spi0.0":
[ 4.375037] 0x000000000000-0x000000040000 : "u-boot"
[ 4.439627] 0x000000040000-0x000000050000 : "u-boot-env"
[ 4.504294] 0x000000050000-0x0000007e0000 : "firmware"
[ 4.568666] 2 uimage-fw partitions found on MTD device firmware
[ 4.639698] Creating 2 MTD partitions on "firmware":
[ 4.699142] 0x000000000000-0x000000300000 : "kernel"
[ 4.760325] 0x000000300000-0x000000790000 : "rootfs"
[ 4.820712] mtd: device 4 (rootfs) set to be root filesystem
[ 4.889550] 1 squashfs-split partitions found on MTD device rootfs
[ 4.963730] 0x0000006e0000-0x000000790000 : "rootfs_data"
[ 5.030119] 0x0000007e0000-0x0000007f0000 : "nvram"
[ 5.089584] 0x0000007f0000-0x000000800000 : "art"
[ 5.566303] ag71xx 19000000.eth: connected to PHY at mdio.0:01 [uid=004dd04e, driver=Generic PHY]
[ 5.673285] eth0: Atheros AG71xx at 0xb9000000, irq 4, mode: rgmii
[ 5.747747] i2c_dev: i2c /dev entries driver
[ 5.800524] NET: Registered PF_INET6 protocol family
[ 5.868507] Segment Routing with IPv6
[ 5.912542] In-situ OAM (IOAM) with IPv6
[ 5.959621] NET: Registered PF_PACKET protocol family
[ 6.020212] 8021q: 802.1Q VLAN Support v1.8
[ 6.111284] Freeing unused kernel image (initmem) memory: 13304K
[ 6.183314] This architecture does not have kernel memory protection.
[ 6.260504] Run /init as init process
[ 6.304358] with arguments:
[ 6.304363] /init
[ 6.304368] with environment:
[ 6.304372] HOME=/
[ 6.304377] TERM=linux
[ 6.886244] init: Console is alive
[ 6.927549] init: - watchdog -
[ 6.990829] kmodloader: loading kernel modules from /etc/modules-boot.d/*
[ 7.087298] usbcore: registered new interface driver usbfs
[ 7.153185] usbcore: registered new interface driver hub
[ 7.216946] usbcore: registered new device driver usb
[ 7.290178] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 7.380354] kmodloader: done loading kernel modules from /etc/modules-boot.d/*
[ 7.477424] init: - preinit -
[ 7.834123] random: jshn: uninitialized urandom read (4 bytes read)
[ 8.056025] random: jshn: uninitialized urandom read (4 bytes read)
[ 8.161597] random: jshn: uninitialized urandom read (4 bytes read)
[ 10.642053] procd: - early -
[ 10.677016] procd: - watchdog -
[ 11.304964] procd: - watchdog -
[ 11.344190] procd: - ubus -
[ 11.386856] random: ubusd: uninitialized urandom read (4 bytes read)
[ 11.465533] random: ubusd: uninitialized urandom read (4 bytes read)
[ 11.542268] random: ubusd: uninitialized urandom read (4 bytes read)
[ 11.623007] procd: - init -
[ 12.382196] kmodloader: loading kernel modules from /etc/modules.d/*
[ 12.960033] urngd: v1.0.2 started.
[ 13.057489] Loading modules backported from Linux version v5.15.58-0-g7d8048d4e064
[ 13.148335] Backport generated by backports.git v5.15.58-1-0-g42a95ce7
[ 13.412616] random: crng init done
[ 13.453381] random: 29 urandom warning(s) missed due to ratelimiting
[ 13.646095] PPP generic driver version 2.4.2
[ 13.700808] NET: Registered PF_PPPOX protocol family
[ 13.800649] kmodloader: done loading kernel modules from /etc/modules.d/*
[ 46.347255] br-lan: port 1(eth0) entered blocking state
[ 46.409919] br-lan: port 1(eth0) entered disabled state
[ 46.472779] device eth0 entered promiscuous mode
[ 49.457277] eth0: link up (1000Mbps/Full duplex)
[ 49.576818] br-lan: port 1(eth0) entered blocking state
[ 49.639489] br-lan: port 1(eth0) entered forwarding state
[ 49.838476] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready