[rajesh_05_in]

Thank you @blkt Could you please little elaborate, what do you mean by above statement? I am very new to this.

Could you please point me to steps for this? Router power light is stable and I have connected USB TTL cable which does not move or come to prompt. Only I see as below snippet. How to bring it back to normal?

BootROM - 1.73
Booting from NAND flash

General initialization - Version: 1.0.0
AVS selection from EFUSE disabled (Skip reading EFUSE values)
mvSysEnvIsFlavourReduced: TWSI Read of 'flavor' failed
Detected Device ID 6820
High speed PHY - Version: 2.0

Init RD NAS topology Serdes Lane 3 is USB3
Serdes Lane 4 is SGMII
board SerDes lanes topology details:
| Lane # | Speed| Type |
------------------------------|
| 0 | 6 | SATA0 |
| 1 | 5 | PCIe0 |
| 2 | 6 | SATA1 |
| 3 | 5 | USB3 HOST1 |
| 4 | 5 | PCIe1 |
| 5 | 0 | SGMII2 |
-------------------------------
:** Link is Gen1, check the EP capability
PCIe, Idx 0: Link upgraded to Gen2 based on client cpabilities
:** Link is Gen1, check the EP capability
PCIe, Idx 1: remains Gen1
High speed PHY - Ended Successfully
DDR3 Training Sequence - Ver TIP-1.46.0
mvSysEnvGetTopologyUpdateInfo: TWSI Read failed
DDR3 Training Sequence - Switching XBAR Window to FastPath Window
DDR3 Training Sequence - Ended Successfully
Not detected suspend to RAM indication
BootROM: Image checksum verification PASSED


U-Boot 2013.01 (May 18 2017 - 16:37:44) Marvell version: 2015_T1.QA.0p16

Boot version : v2.0.9

Board: RD-NAS-88F6820-DDR3
SoC: MV88F6820 Rev A0
running 2 CPUs
CPU: ARM Cortex A9 MPCore (Rev 1) LE
CPU 0
CPU @ 1866 [MHz]
L2 @ 933 [MHz]
TClock @ 200 [MHz]
DDR3 @ 933 [MHz]
DDR3 32 Bit Width,FastPath Memory Access, DLB Enabled, ECC Disabled
DRAM: 512 MiB
NAND: 256 MiB
MMC: mv_sdh: 0

[blkt]

Right, you need to start pressing keys on your keyboard after powering on the router to enter u-boot environment.

Silent boot will not give you a visual countdown. This is too far off-topic, so please start a new thread for questions.

Here are some threads for you to read carefully. https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=326162

https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=322210

https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=318554

[rajesh_05_in]

Thank you, CTRL+C worked to enter in u-boot mode. Now I recovered the router. It worked fine.