Hi,
Replying to thread: The system is easily accessible by removing covers (4 screws) and attaching serial cable to motherboard (tx / rx / gnd & 3.3v pins connected and presented) which allows access to remount squashfs and reset root passwd.
CPU revision is 00019374 (Mips 24Kc)
SoC is Qualcomm Atheros QCA9531 rev 2
[ 0.790000] ag71xx_mdio: probed
[ 0.820000] ar8216: Unknown Atheros device [ver=2, rev=1, phy_id=004dd042]
[ 0.850000] ar8216: Unknown Atheros device [ver=2, rev=1, phy_id=004dd042]
[ 0.870000] ar8216: Unknown Atheros device [ver=2, rev=1, phy_id=004dd042]
[ 0.900000] ar8216: Unknown Atheros device [ver=2, rev=1, phy_id=004dd042]
[ 0.920000] ar8216: Unknown Atheros device [ver=2, rev=1, phy_id=004dd042]
[ 0.930000] ag71xx_mdio: probed
[ 0.930000] eth0: Atheros AG71xx at 0xb9000000, irq 4
[ 1.490000] ag71xx ag71xx.0: eth0: connected to PHY at ag71xx-mdio.1:04 [uid=004dd042, driver=Generic PHY]
[ 1.500000] eth1: Atheros AG71xx at 0xba000000, irq 5
[ 2.060000] eth1: Found an AR934X built-in switch
[ 19.830000] ath_hal: 0.9.17.1 (AR5416, AR9380, REGOPS_FUNC, WRITE_EEPROM, TX_DATA_SWAP, RX_DATA_SWAP, 11D)
[ 19.850000] ath_rate_atheros: Copyright (c) 2001-2005 Atheros Communications, Inc, All Rights Reserved
cmdline board=AP147 console=ttyS0,115200 mtdparts=spi0.0:256k(u-boot),64k(u-boot-env),14528k(rootfs),1472k(kernel),64k(art),16000k@0x50000(firmware) rootfstype=squashfs,jffs2 noinitrd
root@XD6700:~# cat /proc/mtd
dev: size erasesize name
mtd0: 00040000 00010000 "u-boot"
mtd1: 00010000 00010000 "u-boot-env"
mtd2: 00e30000 00010000 "rootfs"
mtd3: 00420000 00010000 "rootfs_data"
mtd4: 00170000 00010000 "kernel"
mtd5: 00010000 00010000 "art"
mtd6: 00fa0000 00010000 "firmware"