After connecting a proper serial adapter, a better boot log:
U-Boot 1.1.4-g4fe3722 (Apr 26 2013 - 00:14:18)
AP121 (ar9331) U-boot
DRAM: 32 MB
Top of RAM usable for U-Boot at: 82000000
Reserving 137k for U-Boot at: 81fdc000
Reserving 192k for malloc() at: 81fac000
Reserving 44 Bytes for Board Info at: 81fabfd4
Reserving 36 Bytes for Global Data at: 81fabfb0
Reserving 128k for boot params() at: 81f8bfb0
Stack Pointer at: 81f8bf98
Now running in RAM - U-Boot at: 81fdc000
id read 0x100000ff
flash size 16777216, sector count = 256
Flash: 16 MB
Using default environment
In: serial
Out: serial
Err: serial
Net: ag7240_enet_initialize...
No valid address in Flash. Using fixed address
Fetching MAC Address from 0x81ff36b8
: cfg1 0x5 cfg2 0x7114
eth0: 00:03:7f:09:0b:ad
eth0 up
: cfg1 0xf cfg2 0x7214
eth1: 00:00:b6:ff:79:51
athrs26_reg_init_lan
ATHRS26: resetting s26
ATHRS26: s26 reset done
eth1 up
eth0, eth1
Hit any key to stop autoboot: 0
ar7240>printenv
bootargs=console=none init=/sbin/init
bootcmd=bootm 0x9f010000 ; bootm 0x9f100000
bootdelay=0
baudrate=115200
ethaddr=0x00:0xaa:0xbb:0xcc:0xdd:0xee
ipaddr=192.168.1.2
serverip=192.168.1.10
stdin=serial
stdout=serial
stderr=serial
ethact=eth0
Environment size: 242/65532 bytes
ar7240> setenv bootargs "console=ttyS0,115200 init=/sbin/init"
ar7240> bootm 0x9f010000 ; bootm 0x9f100000
## Booting image at 9f010000 ...
Image Name: Pimento Kernel Image
Created: 2013-04-26 4:10:42 UTC
Image Type: MIPS Linux Kernel Image (lzma compressed)
Data Size: 980444 Bytes = 957.5 kB
Load Address: 80002000
Entry Point: 801dd200
Verifying Checksum at 0x9f010040 ...OK
Uncompressing Kernel Image ... OK
No initrd
## Transferring control to Linux (at address 801dd200) ...
## Giving linux memsize in bytes, 33554432
Starting kernel ...
Booting AR9330(Hornet)...
Linux version 2.6.31-g797da55 (parabuild@vdc01b01ubuntu11) (gcc version 4.5.0 20100729 (prerelease) (GCC) ) #1 Fri Apr 26 00:10:15 EDT 2013
flash_size passed from bootloader = 16
CPU revision is: 00019374 (MIPS 24Kc)
Determined physical RAM map:
memory: 02000000 @ 00000000 (usable)
User-defined physical RAM map:
memory: 02000000 @ 00000000 (usable)
Initrd not found or empty - disabling initrd
Zone PFN ranges:
Normal 0x00000000 -> 0x00002000
Movable zone start PFN for each node
early_node_map[1] active PFN ranges
0: 0x00000000 -> 0x00002000
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 8128
Kernel command line: console=ttyS0,115200 init=/sbin/init mem=32M mtdparts=ar7240-nor0:64k(u-boot),960k(kernel),960k(kernel2),4096k(root),5120k(data),5120k(cache),64k(mfg)
PID hash table entries: 128 (order: 7, 512 bytes)
Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
Primary data cache 32kB, 4-way, VIPT, cache aliases, linesize 32 bytes
Writing ErrCtl register=00000000
Readback ErrCtl register=00000000
Memory: 29708k/32768k available (1913k kernel code, 3060k reserved, 543k data, 232k init, 0k highmem)
NR_IRQS:128
plat_time_init: plat time init done
Calibrating delay loop... 266.24 BogoMIPS (lpj=532480)
Mount-cache hash table entries: 512
NET: Registered protocol family 16
===== ar7240_platform_init: 0
******* USBDCP 1
bio: create slab <bio-0> at 0
SCSI subsystem initialized
Bluetooth: Core ver 2.16
NET: Registered protocol family 31
Bluetooth: HCI device and connection manager initialized
Bluetooth: HCI socket layer initialized
Bluetooth: L2CAP socket layer initialized
Bluetooth: SCO socket layer initialized
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 1024 (order: 1, 8192 bytes)
TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
TCP reno registered
NET: Registered protocol family 1
AR7240 GPIOC major 0
squashfs: version 4.0 (2009/01/31) Phillip Lougher
Registering unionfs 2.5.9.2 (for 2.6.31.14)
JFFS2 version 2.2 (NAND) (ZLIB) (RTIME) (c) 2001-2006 Red Hat, Inc.
msgmni has been set to 58
alg: No test for lzma (lzma-generic)
alg: No test for stdrng (krng)
io scheduler noop registered (default)
Serial: 8250/16550 driver, 1 ports, IRQ sharing disabled
ttyS0: detected caps 00000000 should be 00000100
serial8250.0: ttyS0 at MMIO 0xb8020000 (irq = 19) is a 16550A
console [ttyS0] enabled
brd: module loaded
input: Pimento as /devices/virtual/input/input0
7 cmdlinepart partitions found on MTD device ar7240-nor0
Creating 7 MTD partitions on "ar7240-nor0":
0x000000000000-0x000000010000 : "u-boot"
0x000000010000-0x000000100000 : "kernel"
0x000000100000-0x0000001f0000 : "kernel2"
0x0000001f0000-0x0000005f0000 : "root"
0x0000005f0000-0x000000af0000 : "data"
0x000000af0000-0x000000ff0000 : "cache"
0x000000ff0000-0x000001000000 : "mfg"
Bluetooth: HCI UART driver ver 2.2
Bluetooth: HCI BCSP protocol initialized
TCP cubic registered
NET: Registered protocol family 17
Bluetooth: RFCOMM socket layer initialized
Bluetooth: RFCOMM ver 1.11
802.1Q VLAN Support v1.8 Ben Greear <greearb@candelatech.com>
All bugs added by David S. Miller <davem@redhat.com>
Freeing unused kernel memory: 232k freed
init started: BusyBox v1.13.4 (2013-04-26 00:13:03 EDT)
starting pid 22, tty '': '/etc/init.d/rcS'
mount: mounting rootfs on / failed: No such file or directory
mount: mounting tmpfs on /media/ram failed: No such file or directory
Loading module athrs_gmac
ATHR_GMAC: Length per segment 1536
ATHR_GMAC: fifo cfg 3 01f00140
ATHR_GMAC: Mac address for unit 0:bf7f0000
ATHR_GMAC: 19:85:20:03:00:00
ATHR_GMAC: Max segments per packet : 1
ATHR_GMAC: Max tx descriptor count : 40
ATHR_GMAC: Max rx descriptor count : 252
ATHR_GMAC: Mac capability flags : 4401
ATHR_GMAC: Mac address for unit 1:bf7f0006
ATHR_GMAC: 00:0c:f0:60:dc:98
ATHR_GMAC: Max segments per packet : 1
ATHR_GMAC: Max tx descriptor count : 40
ATHR_GMAC: Max rx descriptor count : 96
ATHR_GMAC: Mac capability flags : 4D81
Loading module ath_i2s
Loading module cc2544
cc2544 chipid 0x4411
Loading module kernel/drivers/usb/gadget/ath_udc
ath_usb_init: id: 111
queue head a1e07000 1e07000 Allocated
Loading module kernel/drivers/usb/gadget/gadgetfs
gadgetfs: USB Gadget filesystem, version 24 Aug 2004
Loading module asf
athr_gmac_ring_alloc Allocated 640 at 0x81e05400
athr_gmac_ring_alloc Allocated 1536 at 0x81c55000
Setting Drop CRC Errors, Pause Frames and Length Error frames
ATHRS26: resetting s26
ATHRS26: s26 reset done
Setting PHY...
asf: module license 'Proprietary' taints kernel.
Disabling lock debugging due to kernel taint
Loading module adf
Loading module ath_hal
ath_hal: 0.9.17.1 (AR9380, REGOPS_FUNC, WRITE_EEPROM, 11D)
Loading module ath_rate_atheros
ath_rate_atheros: Copyright (c) 2001-2005 Atheros Communications, Inc, All Rights Reserved
Loading module ath_dev
ath_dev: Copyright (c) 2001-2007 Atheros Communications, Inc, All Rights Reserved
Loading module umac
ath_ahb: 9.2.0_U10.5.13 (Atheros/multi-bss)
__ath_attach: Set global_scn[0]
ACBKMinfree = 48
ACBEMinfree = 32
ACVIMinfree = 16
ACVOMinfree = 0
CABMinfree = 48
UAPSDMinfree = 0
Restoring Cal data from Flash
ath_get_caps[5123] rx chainmask mismatch actual 1 sc_chainmak 0
ath_get_caps[5098] tx chainmask mismatch actual 1 sc_chainmak 0
wifi0: Atheros 9380: mem=0xb8100000, irq=2
wlan_vap_create : enter. devhandle=0x814642c0, opmode=IEEE80211_M_STA, flags=0x1
wlan_vap_create : exit. devhandle=0x814642c0, opmode=IEEE80211_M_STA, flags=0x1.
VAP device ath0 created
ath0
ieee80211_ioctl_siwmode: imr.ifm_active=131200, new mode=2, valid=1
udhcpc (v1.13.4) started
Sending discover...
unionfs: new lower inode mtime (bindex=1, name=ttyS0)
Loading PSKEY_RX_MR_SAMP_CONFIG ... done
Loading 0x212c ... done
Loading 0x212d ... done
Loading 0x212e ... done
Loading 0x212f ... done
Loading 0x2130 ... done
Loading 0x2131 ... done
Loading 0x2139 ... done
Loading 0x213a ... done
Loading 0x213b ... done
Loading 0x2200 ... done
Loading PSKEY_ANA_FREQ ... done
Loading PSKEY_HOST_INTERFACE ... done
Loading 0x01ea ... done
Loading 0x2578 ... done
Loading PSKEY_CLOCK_REQUEST_ENABLE ... done
Loading PSKEY_LC_DEFAULT_TX_POWER ... done
Loading PSKEY_LC_MAX_TX_POWER ... done
Loading PSKEY_ANA_FTRIM ... done
Loading PSKEY_BDADDR ... done
unionfs: new lower inode mtime (bindex=1, name=ttyS0)
Bluetooth: Out-of-order packet arrived, got 1 expected 0