Miałeś rację kostka FLASH uszkodzona. Nie mogłem zweryfikować obrazu po wgraniu programatorem. Niestety na nowej kości dzieję się to samo 
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* U-Boot 1.1.4-b29f18ad-clean *
* Build: 2017-08-31 *
***************************************
** Warning: reset caused by watchdog!
BOARD: TP-Link TL-MR3420 v2
SOC: AR9341 rev. 3
CPU: MIPS 74Kc
RAM: 64 MB DDR1 16-bit CL3-3-3-8
FLASH: 16 MB Winbond W25Q128
MAC: 00:03:7F:09:0B:AD
CLOCKS: CPU/RAM/AHB/SPI/REF
550/400/200/ 25/ 25 MHz
Hit any key to stop booting: 0
Booting image from 0x9F020000...
Vendor/image name: OpenWrt r3514-97ebdf9
Hardware ID: 0x34200002
Whole image size: 3.8 MB (3932160 bytes)
Kernel size: 1.3 MB (1359556 bytes)
Rootfs size: 2.1 MB (2176342 bytes)
Kernel load address: 0x80060000
Kernel entry point: 0x80060000
Header CRC... skipped
Data CRC... skipped
Stopping network... OK!
Uncompressing Kernel... OK!
Starting kernel...
[ 0.000000] Linux version 4.4.87 (cezary@eko.one.pl) (gcc version 5.4.0 (LEDE GCC 5.4.0 r3103-1b51a49) ) #0 Thu Sep 14 18:47:54 2017
[ 0.000000] bootconsole [early0] enabled
[ 0.000000] CPU0 revision is: 0001974c (MIPS 74Kc)
[ 0.000000] SoC: Atheros AR9341 rev 3
[ 0.000000] Determined physical RAM map:
[ 0.000000] memory: 04000000 @ 00000000 (usable)
[ 0.000000] Initrd not found or empty - disabling initrd
[ 0.000000] No valid device tree found, continuing without
[ 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] 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] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16256
[ 0.000000] Kernel command line: board=TL-MR3420-v2 console=ttyS0,115200 rootfstype=squashfs,jffs2 noinitrd
[ 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=00000000
[ 0.000000] Readback ErrCtl register=00000000
[ 0.000000] Memory: 59968K/65536K available (3100K kernel code, 163K rwdata, 776K rodata, 304K init, 205K bss, 5568K 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] Clocks: CPU:550.000MHz, DDR:400.000MHz, AHB:200.000MHz, Ref:25.000MHz
[ 0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 6950037990 ns
[ 0.000010] sched_clock: 32 bits at 275MHz, resolution 3ns, wraps every 7809031678ns
[ 0.008865] Calibrating delay loop... 274.02 BogoMIPS (lpj=1370112)
[ 0.081886] pid_max: default: 32768 minimum: 301
[ 0.087268] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.094791] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.105720] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.116943] futex hash table entries: 256 (order: -1, 3072 bytes)
[ 0.125316] NET: Registered protocol family 16
[ 0.132040] MIPS: machine is TP-LINK TL-MR3420 v2
[ 0.588857] clocksource: Switched to clocksource MIPS
[ 0.596114] NET: Registered protocol family 2
[ 0.602098] TCP established hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.610085] TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.617316] TCP: Hash tables configured (established 1024 bind 1024)
[ 0.624639] UDP hash table entries: 256 (order: 0, 4096 bytes)
[ 0.631317] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
[ 0.638762] NET: Registered protocol family 1
[ 0.648771] Crashlog allocated RAM at address 0x3f00000
[ 0.671838] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 0.678472] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
[ 0.692539] io scheduler noop registered
[ 0.697000] io scheduler deadline registered (default)
[ 0.703164] Serial: 8250/16550 driver, 16 ports, IRQ sharing enabled
[ 0.713482] console [ttyS0] disabled
� 0.737653] serial8250.0: ttyS0 at MMIO 0x18020000 (irq = 11, base_baud = 1562500) is a 16550A
[ 0.747459] console [ttyS0] enabled
[ 0.747459] console [ttyS0] enabled
[ 0.755014] bootconsole [early0] disabled
[ 0.755014] bootconsole [early0] disabled
[ 0.769525] m25p80 spi0.0: found w25q128, expected m25p80
[ 0.775119] m25p80 spi0.0: w25q128 (16384 Kbytes)
[ 0.781302] 5 tp-link partitions found on MTD device spi0.0
[ 0.787063] Creating 5 MTD partitions on "spi0.0":
[ 0.792066] 0x000000000000-0x000000020000 : "u-boot"
[ 0.798814] 0x000000020000-0x00000016c0c4 : "kernel"
[ 0.805851] 0x00000016c0c4-0x000000ff0000 : "rootfs"
[ 0.812847] mtd: device 2 (rootfs) set to be root filesystem
[ 0.818732] 1 squashfs-split partitions found on MTD device rootfs
[ 0.825184] 0x000000380000-0x000000ff0000 : "rootfs_data"
[ 0.832637] 0x000000ff0000-0x000001000000 : "art"
[ 0.839424] 0x000000020000-0x000000ff0000 : "firmware"
[ 0.864170] libphy: ag71xx_mdio: probed
[ 1.450945] ag71xx ag71xx.0: connected to PHY at ag71xx-mdio.1:00 [uid=004dd042, driver=Generic PHY]
[ 1.461177] eth0: Atheros AG71xx at 0xb9000000, irq 4, mode:MII
[ 2.050739] ag71xx-mdio.1: Found an AR934X built-in switch
[ 2.093069] eth1: Atheros AG71xx at 0xba000000, irq 5, mode:GMII
[ 2.102259] NET: Registered protocol family 10
[ 2.112002] NET: Registered protocol family 17
[ 2.116685] bridge: automatic filtering via arp/ip/ip6tables has been deprecated. Update your scripts to load br_netfilter if you need this.
[ 2.129914] 8021q: 802.1Q VLAN Support v1.8
[ 2.142388] VFS: Mounted root (squashfs filesystem) readonly on device 31:2.
[ 2.151698] Freeing unused kernel memory: 304K
[ 3.179016] init: Console is alive
[ 3.182777] init: - watchdog -
[ 4.483406] kmodloader: loading kernel modules from /etc/modules-boot.d/*
[ 4.621552] usbcore: registered new interface driver usbfs
[ 4.627362] usbcore: registered new interface driver hub
[ 4.633012] usbcore: registered new device driver usb
[ 4.687156] SCSI subsystem initialized
[ 4.698281] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 4.706919] ehci-platform: EHCI generic platform driver
[ 4.712521] ehci-platform ehci-platform: EHCI Host Controller
[ 4.718505] ehci-platform ehci-platform: new USB bus registered, assigned bus number 1
[ 4.728800] ehci-platform ehci-platform: TX-TX IDP fix enabled
[ 4.734864] ehci-platform ehci-platform: irq 3, io mem 0x1b000000
[ 4.758903] ehci-platform ehci-platform: USB 2.0 started, EHCI 1.00
[ 4.766421] hub 1-0:1.0: USB hub found
[ 4.770729] hub 1-0:1.0: 1 port detected
[ 4.780048] usbcore: registered new interface driver usb-storage
[ 4.787077] kmodloader: done loading kernel modules from /etc/modules-boot.d/*
[ 4.796947] init: - preinit -
[ 5.503966] IPv6: ADDRCONF(NETDEV_UP): eth1: link is not ready
[ 5.532700] random: procd: uninitialized urandom read (4 bytes read, 9 bits of entropy available)
Press the [f] key and hit [enter] to enter failsafe mode
Press the [1], [2], [3] or [4] key and hit [enter] to select the debug level
[ 8.100126] eth1: link up (1000Mbps/Full duplex)
[ 8.104937] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
cat: can't open '�keypress_true=': No such file or directory
[ 8.753823] mount_root: loading kmods from internal overlay
[ 8.782234] kmodloader: loading kernel modules from //etc/modules-boot.d/*
[ 8.790998] kmodloader: done loading kernel modules from //etc/modules-boot.d/*
[ 9.088582] block: attempting to load /etc/config/fstab
[ 9.094373] block: unable to load configuration (fstab: Entry not found)
[ 9.101688] block: no usable configuration
[ 9.106665] mount_root: jffs2 not ready yet, using temporary tmpfs overlay
[ 9.118395] urandom-seed: Seed file not found (/etc/urandom.seed)
[ 9.157989] eth1: link down
[ 9.173397] procd: - early -
[ 9.176494] procd: - watchdog -
[ 9.820195] procd: - watchdog -
[ 9.823753] procd: - ubus -
[ 10.090870] random: ubusd: uninitialized urandom read (4 bytes read, 16 bits of entropy available)
[ 10.100752] random: ubusd: uninitialized urandom read (4 bytes read, 17 bits of entropy available)
[ 10.110203] random: ubusd: uninitialized urandom read (4 bytes read, 17 bits of entropy available)
[ 10.119946] random: ubusd: uninitialized urandom read (4 bytes read, 17 bits of entropy available)
[ 10.129353] random: ubusd: uninitialized urandom read (4 bytes read, 17 bits of entropy available)
[ 10.138906] random: ubusd: uninitialized urandom read (4 bytes read, 17 bits of entropy available)
[ 10.148409] random: ubusd: uninitialized urandom read (4 bytes read, 17 bits of entropy available)
[ 10.158231] procd: - init -
Please press Enter to activate this console.
[ 10.425725] kmodloader: loading kernel modules from /etc/modules.d/*
[ 10.440550] Loading modules backported from Linux version wt-2017-01-31-0-ge882dff19e7f
[ 10.448828] Backport generated by backports.git backports-20160324-13-g24da7d3c
[ 10.465182] nf_conntrack version 0.5.0 (941 buckets, 3764 max)
[ 10.512973] xt_time: kernel timezone is -0000
[ 10.542197] ip_tables: (C) 2000-2006 Netfilter Core Team
[ 10.600275] PPP generic driver version 2.4.2
[ 10.607671] NET: Registered protocol family 24
[ 10.685319] ieee80211 phy0: Atheros AR9340 Rev:3 mem=0xb8100000, irq=47
[ 10.811291] kmodloader: done loading kernel modules from /etc/modules.d/*
[ 10.965481] SQUASHFS error: xz decompression failed, data probably corrupt
[ 10.972627] SQUASHFS error: squashfs_read_data failed to read block 0x1f81e2
[ 10.979919] SQUASHFS error: Unable to read fragment cache entry [1f81e2]
[ 10.986841] SQUASHFS error: Unable to read page, block 1f81e2, size 17c98
[ 10.993892] SQUASHFS error: Unable to read fragment cache entry [1f81e2]
[ 11.000820] SQUASHFS error: Unable to read page, block 1f81e2, size 17c98
[ 11.007862] SQUASHFS error: Unable to read fragment cache entry [1f81e2]
[ 11.014790] SQUASHFS error: Unable to read page, block 1f81e2, size 17c98
[ 11.110347]
do_page_fault(): sending SIGSEGV to uci for invalid read access from 00000004
[ 11.118797] epc = 77811bbc in libc.so[7778e000+92000]
[ 11.124136] ra = 77811bb4 in libc.so[7778e000+92000]
[ 11.129391]
[ 11.664569]
do_page_fault(): sending SIGSEGV to hotplug-call for invalid read access from 00e162fc
[ 11.673889] epc = 0041ad47 in busybox[400000+4c000]
[ 11.678982] ra = 0041ad45 in busybox[400000+4c000]
[ 11.684042]
[ 11.823246]
do_page_fault(): sending SIGSEGV to sleep for invalid read access from 77d7c2d8
[ 11.831895] epc = 77d55780 in libc.so[77cd2000+92000]
[ 11.837156] ra = 77d55770 in libc.so[77cd2000+92000]
[ 11.842411]
[ 11.936201] SQUASHFS error: xz decompression failed, data probably corrupt
[ 11.943353] SQUASHFS error: squashfs_read_data failed to read block 0x1f81e2
[ 11.950651] SQUASHFS error: Unable to read fragment cache entry [1f81e2]
[ 11.957576] SQUASHFS error: Unable to read page, block 1f81e2, size 17c98
[ 11.990380] SQUASHFS error: Unable to read fragment cache entry [1f81e2]
[ 11.997315] SQUASHFS error: Unable to read page, block 1f81e2, size 17c98
[ 12.098999]
do_page_fault(): sending SIGSEGV to procd for invalid write access to 00000045
[ 12.107542] epc = 77663fc0 in libc.so[775f2000+92000]
[ 12.112828] ra = 77661910 in libc.so[775f2000+92000]
[ 12.118073]
[ 12.148234] SQUASHFS error: Unable to read fragment cache entry [1f81e2]
[ 12.155236] SQUASHFS error: Unable to read page, block 1f81e2, size 17c98
[ 12.244049] SQUASHFS error: Unable to read fragment cache entry [1f81e2]
[ 12.251040] SQUASHFS error: Unable to read page, block 1f81e2, size 17c98
[ 12.331739] SQUASHFS error: Unable to read fragment cache entry [1f81e2]
[ 12.338673] SQUASHFS error: Unable to read page, block 1f81e2, size 17c98
[ 12.576738]
do_page_fault(): sending SIGSEGV to basename for invalid read access from 77080168
[ 12.585740] epc = 77126250 in libc.so[770a4000+92000]
[ 12.591018] ra = 771261e4 in libc.so[770a4000+92000]
[ 12.596250]
[ 13.059680] CPU 0 Unable to handle kernel paging request at virtual address 05858340, epc == 80120be4, ra == 800829dc
[ 13.070726] Oops[#1]:
[ 13.073086] CPU: 0 PID: 720 Comm: rm Not tainted 4.4.87 #0
[ 13.078752] task: 83921928 ti: 82c36000 task.ti: 82c36000
[ 13.084328] $ 0 : 00000000 00000001 05858340 00000020
[ 13.089766] $ 4 : 82c2c180 08100020 804d0000 830061e0
[ 13.095197] $ 8 : 00002993 83b21f78 00000001 00000000
[ 13.100626] $12 : 8108217c 00000024 804c0000 ffffff80
[ 13.106055] $16 : 82c2c180 82c2c194 00000000 00000807
[ 13.111485] $20 : 00000000 00000000 77a67518 77a68d8c
[ 13.116914] $24 : 81082188 00000100
[ 13.122345] $28 : 82c36000 82c37e90 00000000 800829dc
[ 13.127775] Hi : 000001cb
[ 13.130750] Lo : 00001e75
[ 13.133751] epc : 80120be4 put_files_struct+0x80/0x110
[ 13.139250] ra : 800829dc do_exit+0x2d4/0x704
[ 13.144011] Status: 1100fc03 KERNEL EXL IE
[ 13.148358] Cause : 00800008 (ExcCode 02)
[ 13.152496] BadVA : 05858340
[ 13.155473] PrId : 0001974c (MIPS 74Kc)
[ 13.159520] Modules linked in: ath9k ath9k_common pppoe ppp_async iptable_nat ath9k_hw ath pppox ppp_generic nf_nat_ipv4 nf_conntrack_ipv4 mac80211 iptable_mangle iptable_filter ipt_REJECT ipt_MASQUERADE ip_tables cfg80211 xt_time xt_tcpudp xt_state xt_nat xt_multiport xt_mark xt_mac xt_limit xt_conntrack xt_comment xt_TCPMSS xt_REDIRECT xt_LOG xt_CT x_tables slhc nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_nat nf_log_ipv4 nf_log_common nf_defrag_ipv4 nf_conntrack_rtcache nf_conntrack crc_ccitt compat ledtrig_usbport usb_storage ehci_platform ehci_hcd sd_mod scsi_mod gpio_button_hotplug ext4 jbd2 mbcache usbcore nls_base usb_common crc16 crc32c_generic crypto_hash
[ 13.221916] Process rm (pid: 720, threadinfo=82c36000, task=83921928, tls=77a6fd48)
[ 13.229819] Stack : 83921928 83a5f180 83921928 83a5f180 83921928 83a5f180 00000000 83a5f1b4
77a64000 800829dc 834af000 00000000 00000000 801152a0 00000012 00000000
00000000 7fb81f34 00000003 0040788d 77a64000 77a64000 77a67518 77a68d8c
00000000 80083a78 82c20010 ffffff9c 7fb82f7a 00000000 00000000 80083ae8
77a64000 77a64000 77a67518 77a68d8c 00000000 80062c6c 00000001 775df3d0
...
[ 13.266808] Call Trace:
[ 13.269343] [<80120be4>] put_files_struct+0x80/0x110
[ 13.274479] [<800829dc>] do_exit+0x2d4/0x704
[ 13.278893] [<80083a78>] do_group_exit+0x48/0xa4
[ 13.283669] [<80083ae8>] __wake_up_parent+0x0/0x18
[ 13.288615]
[ 13.290156]
Code: 00000000 8e220004 00541021 <c0440000> 00001821 e0430000 1060fffc 00000000 10800007
[ 13.300506] ---[ end trace d2f725c7020ff9e7 ]---
[ 13.307595] Fatal exception: panic in 5 seconds
[ 14.189718] reboot: Restarting system