mt7925e: Unhandled kernel unaligned access on MIPS (Big-Endian)

Hi, I have a rare and unusual configuration here. 0:)
I really like OpenWrt + TP-Link Archer C7 AC1750, I have V2, V4, and V5.
On the C7 V2 I just replaced original ath10k 5GHz miniPCIe WiFi 5 card to an AzureWave M.2 E-Key WiFi 7 card AW-EB600NF (in M.2 E-Key adapter) with MT7925B22M.

Router: TP-Link Archer C7 v2 (QCA9558, MIPS 74Kc, Big-Endian)
OpenWrt: 25.12.0-rc5, r32673-482ba7230a
Kernel: Linux version 6.12.71 (builder@buildhost) (mips-openwrt-linux-musl-gcc (OpenWrt GCC 14.3.0 r32673-482ba7230a) 14.3.0, GNU ld (GNU Binutils) 2.44) #0 Tue Feb 17 21:30:37 2026
Card: MT7925 PCIe

Playing with:

WIFI_MT7925_PATCH_MCU_1_1_hdr.bin
WIFI_RAM_CODE_MT7925_1_1.bin

With the original kmod-mt7925e kmod-mt7925-firmware packages from OpenWrt, boot hangs, then watchdog takes over.
BTW, "____000000" looks weird.

...
[   23.220895] mt7925e 0000:00:00.0: enabling device (0000 -> 0002)
[   24.119453] mt7925e 0000:00:00.0: ASIC revision: 79250000
[   24.236494] mt7925e 0000:00:00.0: HW/SW Version: 0x8a108a10, Build Time: 20231227093012a
[   24.236494]
[   24.333372] ieee80211 phy1: Atheros AR9550 Rev:0 mem=0x2b382f0c, irq=15
[   24.430742] kmodloader: done loading kernel modules from /etc/modules.d/*
[   24.735555] mt7925e 0000:00:00.0: WM Firmware Version: ____000000, Build Time: 20231227093232

U-Boot 1.1.4 (Mar  5 2018 - 13:57:29)
...

On some newer firmware 20251210092928a + 20251210093025 that I find here:
linux-firmware: update firmware for MT7925 devices
or 20260106153007a + 20260106153120 from here:
mt7925

I get an error Unhandled kernel unaligned access[#1] in the kernel:

root@OpenWrt:/# modprobe mt7925e
[ 620.583743] mt7925e 0000:00:00.0: enabling device (0000 -> 0002)
[ 621.411575] mt7925e 0000:00:00.0: ASIC revision: 79250000
root@OpenWrtOld:/# [ 2621.635324] mt7925e 0000:00:00.0: HW/SW Version: 0x8a108a10, Build Time: 20260106153007a
[ 621.635324]
[ 621.992939] mt7925e 0000:00:00.0: WM Firmware Version: ____000000, Build Time: 20260106153120
[ 622.861532] ------------[ cut here ]------------
[ 622.866236] WARNING: CPU: 0 PID: 293 at kernel/workqueue.c:2257 0x800e3d7c
[ 622.873220] Modules linked in: mt7925e(O) mt7925_common(O) mt792x_lib(O) mt76_connac_lib(O) mt76(O) hwmon ath9k(O) ath9k_common(O) pppoe ▒▒▒▒(PFCOEKXTN)
[ 622.873298] Unhandled kernel unaligned access[#1]:
[ 622.891985] CPU: 0 UID: 0 PID: 293 Comm: kworker/0:3 Tainted: G           O       6.12.71 #0
[ 622.900556] Tainted: [O]=OOT_MODULE
[ 622.904090] Hardware name: TP-Link Archer C7 v2
[ 622.908686] Workqueue: events 0x82c4f06c [mt7925_common@b5edcfec+0x11000]
[ 622.915591] $ 0   : 00000000 00000001 ffffffff 00000027
[ 622.920915] $ 4   : 8085f580 8085f580 00000000 8180dcf0
[ 622.926240] $ 8   : ffffefff 00000000 ffffffea 000000a0
[ 622.931563] $12   : 8180dcfc 000000a0 8085f610 ffffffff
[ 622.936887] $16   : fffffffb 8076c4a0 808c58dc 80850000
[ 622.942211] $20   : 00000003 000008d1 808c0000 00038b64
[ 622.947536] $24   : 00000002 fffc2637
[ 622.952859] $28   : 81c44000 8180de10 808c5a40 800e19fc
[ 622.958183] Hi    : 001ebb7b
[ 622.961105] Lo    : 0bedb37a
[ 622.964027] epc   : 800e19d4 0x800e19d4
[ 622.967916] ra    : 800e19fc 0x800e19fc
[ 622.971806] Status: 1100fc02 KERNEL EXL
[ 622.975793] Cause : 40808010 (ExcCode 04)
[ 622.979857] BadVA : fffffffb
[ 622.982780] PrId  : 00019750 (MIPS 74Kc)
[ 622.986757] Modules linked in: mt7925e(O) mt7925_common(O) mt792x_lib(O) mt76_connac_lib(O) mt76(O) hwmon ath9k(O) ath9k_common(O) pppoe ▒▒▒▒(PFCOEKXTN)
[ 622.986819] Unhandled kernel unaligned access[#2]:
[ 623.005504] CPU: 0 UID: 0 PID: 293 Comm: kworker/0:3 Tainted: G           O       6.12.71 #0
...

Important part of kernel log:

...
[    1.869808] PCI host bridge to bus 0000:00
[    1.874039] pci_bus 0000:00: root bus resource [mem 0x12000000-0x13ffffff]
[    1.881031] pci_bus 0000:00: root bus resource [io  0x0001]
[    1.886706] pci_bus 0000:00: No busn resource found for root bus, will use [bus 00-ff]
[    1.894870] pci 0000:00:00.0: [14c3:7925] type 00 class 0x028000 PCIe Endpoint
[    1.902253] pci 0000:00:00.0: BAR 0 [mem 0x00000000-0x001fffff 64bit]
[    1.908848] pci 0000:00:00.0: BAR 2 [mem 0x00000000-0x00007fff 64bit]
[    1.915540] pci 0000:00:00.0: PME# supported from D0 D3hot D3cold
[    1.921757] pci 0000:00:00.0: 2.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x1 link at 0000:00:00.0 (capable of 4.000 Gb/s with 5.0 GT/s PCIe x1 link)
[    1.938065] pci_bus 0000:00: busn_res: [bus 00-ff] end is updated to 00
[    1.944847] pci 0000:00:00.0: BAR 0 [mem 0x12000000-0x121fffff 64bit]: assigned
[    1.952299] pci 0000:00:00.0: BAR 2 [mem 0x12200000-0x12207fff 64bit]: assigned
...

Does anyone have any idea what's wrong and how to fix it?
How else can I contribute to getting this working?
Is it realistic that it could work one day? =)
Thank you!

The issue points to the mt7925e driver and mt7925_common workqueue on a MIPS big-endian Archer C7. Reproduce with modprobe mt7925e using the reported firmware and kernel versions, then use the unaligned-access trace to locate the failing path and compare behavior across firmware versions. Done means the fault’s source and a verified fix or clearly documented compatibility limitation are established.