i have also a rt-n56u in boot loop.
i cannot exactly remember what was the root cause. in think i have flashed some trunk version and with "sysupgrade" i also did a factory reset.
somewhere there was the information that this will brick the device?
i tried everything, but the IP cable from Router to my PC is always detected as "unconnected".
That means the IP ports of the router are not working and because of that also the TFTP recovery cannot work.
I also tried to play with the serial console and uboot, but i cannot stop this autoreboot
(my ttl adapter is from pollin)
Is there any chance to bring the device back in a normal state?
Can i flash the uboot via serial connection?
the uboot i have found here:
The output of the serial interface looks like:
Starting kernel ...
[ 0.000000] Linux version 4.4.47 (buildbot@builds-02.infra.lede-project.org) (gcc version 5.4.0 (LEDE GCC 5.4.0 r3103-1b51a49) ) #0 Mon Feb 6 21:34:28 2017
[ 0.000000] SoC Type: Ralink RT3883 ver:1 eco:5:
[ 2.340439] 4 ofpart partitions found on MTD device 1c000000.nor-flash
[ 2.353502] Creating 4 MTD partitions on "1c000000.nor-flash":
[ 2.365139] 0x000000000000-0x000000030000 : "u-boot"
[ 2.376910] 0x000000030000-0x000000040000 : "u-boot-env"
[ 2.389699] 0x000000040000-0x000000050000 : "factory"
[ 2.401865] 0x000000050000-0x000000800000 : "firmware"
[ 2.417068] rtl8367 rtl8367: using GPIO pins 1 (SDA) and 2 (SCK)
[ 2.429223] rtl8367 rtl8367: ACK timeout
[ 2.437047] rtl8367 rtl8367: unable to read chip number
[ 2.447469] rtl8367 rtl8367: chip detection failed, err=-145
[ 2.458777] rtl8367: probe of rtl8367 failed with error -145
[ 2.472008] mtk_soc_eth 10100000.ethernet: using fixed link parameters
[ 2.485078] mtk_soc_eth 10100000.ethernet eth0 (uninitialized): link up (1000Mbps/Full duplex)
[ 2.503055] mtk_soc_eth 10100000.ethernet eth0: mediatek frame engine at 0xb0100000, irq 5
[ 2.520190] rt2880_wdt 10000120.watchdog: Initialized
[ 2.531777] NET: Registered protocol family 10
[ 2.544824] NET: Registered protocol family 17
[ 2.553841] bridge: automatic filtering via arp/ip/ip6tables has been deprecated. Update your scripts to load br_netfilter if you need this.
[ 2.578993] 8021q: 802.1Q VLAN Support v1.8
[ 2.590562] VFS: Cannot open root device "(null)" or unknown-block(0,0): error -6
[ 2.605550] Please append a correct "root=" boot option; here are the available partitions:
[ 2.622212] 1f00 192 mtdblock0 (driver?)
[ 2.632288] 1f01 64 mtdblock1 (driver?)
[ 2.642360] 1f02 64 mtdblock2 (driver?)
[ 2.652432] 1f03 7872 mtdblock3 (driver?)
[ 2.662502] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
[ 2.680044] Rebooting in 1 seconds..
U-Boot 1.1.3 (Jan 12 2011 - 11:35:36)
Board: Ralink APSoC DRAM: 64 MB
relocate_code Pointer at: 837c4000
Software System Reset Occurred
flash_protect ON: from 0xBC000000 to 0xBC02AFAF
flash_protect ON: from 0xBC030000 to 0xBC030FFF
*** Warning - bad CRC, using default environment
Ralink UBoot Version: 3.5.2.0
ASIC 3883_MP (MAC to VITESSE Mode)
DRAM component: 1024 Mbits DDR, width 16
DRAM bus: 16 bit
Total memory: 128 MBytes
Flash component: NOR Flash
Date:Jan 12 2011 Time:11:35:36
icache: sets:512, ways:4, linesz:32 ,total:65536
dcache: sets:256, ways:4, linesz:32 ,total:32768
The CPU freq = 500 MHZ
estimate memory size =64 Mbytes
Please choose the operation:
1: Load system code to SDRAM via TFTP.
2: Load system code then write to Flash via TFTP.
3: Boot system code via Flash (default).
4: Entr boot command line interface.
7: Load Boot Loader code then write to Flash via Serial.
9: Load Boot Loader code then write to Flash via TFTP.
You choosed 3
early Realtek giga Mac support...
GPIOMODE current: 181c
GPIOMODE writing: 181d
GPIOMODE current: 181d
get reg 0x1300: 837ee158
.....
When i reset into the failsafe mode i see the following messages, but as the IP ports are dead nothing can be done:
U-Boot 1.1.3 (Jan 12 2011 - 11:35:36)
Board: Ralink APSoC DRAM: 64 MB
relocate_code Pointer at: 837c4000
flash_protect ON: from 0xBC000000 to 0xBC02AFAF
flash_protect ON: from 0xBC030000 to 0xBC030FFF
*** Warning - bad CRC, using default environment
Ralink UBoot Version: 3.5.2.0
ASIC 3883_MP (MAC to VITESSE Mode)
DRAM component: 1024 Mbits DDR, width 16
DRAM bus: 16 bit
Total memory: 128 MBytes
Flash component: NOR Flash
Date:Jan 12 2011 Time:11:35:36
icache: sets:512, ways:4, linesz:32 ,total:65536
dcache: sets:256, ways:4, linesz:32 ,total:32768
The CPU freq = 500 MHZ
estimate memory size =64 Mbytes
Please choose the operation:
1: Load system code to SDRAM via TFTP.
2: Load system code then write to Flash via TFTP.
3: Boot system code via Flash (default).
4: Entr boot command line interface.
7: Load Boot Loader code then write to Flash via Serial.
9: Load Boot Loader code then write to Flash via TFTP.
You choosed 3
0
early Realtek giga Mac support...
GPIOMODE current: 181c
GPIOMODE writing: 181d
GPIOMODE current: 181d
get reg 0x1300: 837ee158
....
get reg 0x1300: 837ee158
rtk_switch_init(): return 14
rtl8367m_switch_init_pre() return 14
Bootloader version: 1.0.0.6
MAC Address: 20:CF:30:B7:A2:49
GPIOMODE before: 181d
GPIOMODE writing: 181d
GPIOMODE restoring: 181d
BTN_RESET pressed
Enter Rescue Mode
3: System Boot system code via TFTP.
NetTxPacket = 0x838072C0
KSEG1ADDR(NetTxPacket) = 0xA38072C0
NetLoop,call eth_halt !
NetLoop,call eth_init !
Trying Eth0 (10/100-M)
Waitting for RX_DMA_BUSY status Start... done
set MDIO_CFG as MAC_FORCE, SPD 1000M, FULL_DUPLEX
Realtek giga Mac support..
software reset RTL8367M...
get reg 0x1300: 837d0654
....
get reg 0x1300: 837d0654
rtk_switch_init(): return 14
rtl8367m_switch_init() return 14
Header Payload scatter function is Disable !!
ETH_STATE_ACTIVE!!
Using Eth0 (10/100-M) device
Our IP address is:(192.168.1.1)
Wait for TFTP request...
T T T T T T T T T T T T T T