Bricked RT-AC68U takes only OpenWRT

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TheCoder
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Joined: 16 Feb 2020
Posts: 5

PostPosted: Sun Feb 16, 2020 17:03    Post subject: Bricked RT-AC68U takes only OpenWRT Reply with quote
On my router RT-AC68U rev. E1 (white) I went from AsuswrtMerlin RT-AC68U_384.14_2 to fresh tomato-RT-AC68U-ARM-2020.1-AIO-64K. It was a mistake because I should have flashed the NG version for E1...

Recovery works fine but the router takes only one firmware amongst dozens of others I have created. Only 6 MB OpenWRT is working. Any other soft I put make router to bootloop. I've tried many softs smaller than 32mb but it doesn't help...

Whenever via serial and TFTP I try to put the software, anytime progress is reaching approximately 15th megabyte I am getting an error:

Code:
CFE> flash -noheader : flash1.trx
Reading ::
TFTP Server.
..tftp retry wait 0
break!! reach max retry!!
Failed.: I/O error
*** command status = -4


However, VPN versions of Tomato (12 mb) are successfully transferred to the router but the router is stuck in bootloop.

Any soft I put via CFE and Asus Restoration Tool it says that the flashing is successful but the router cannot boot to the system. Of course each time I am clearing the NVRAM but it doesn't change anything.

I haven't flash CFE, etc.

Can anything be done via serial to revive the router? I would be glad for any tips.
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kernel-panic69
DD-WRT Guru


Joined: 08 May 2018
Posts: 3410
Location: Texas, USA

PostPosted: Sun Feb 16, 2020 19:38    Post subject: Reply with quote
Doesn't Asus have a built in recovery / rescue mode? Pretty sure you have to flash back to stock firmware.
_________________
E4200 v1 DD-WRT 42287 mega (02/06/20) K3.x
R7000P DD-WRT 40270M kongac
E4200 v1 FreshTomato 2020.1
E4200 v1 FreshTomato 2020.2.development
R7000 FreshTomato 2020.2.development
E4200 v1 1.0.07.development
WRT3200ACM OpenWRT 18.06.6
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Linux User #377467 counter.li.org / linuxcounter.net
TheCoder
DD-WRT Novice


Joined: 16 Feb 2020
Posts: 5

PostPosted: Sun Feb 16, 2020 20:12    Post subject: Reply with quote
The router doesn't work on any other software applied via recovery mode... Unfortunately, my problem is not common
kernel-panic69
DD-WRT Guru


Joined: 08 May 2018
Posts: 3410
Location: Texas, USA

PostPosted: Mon Feb 17, 2020 1:31    Post subject: Reply with quote
Asus cfe miniweb server, not the Restoration utility.
_________________
E4200 v1 DD-WRT 42287 mega (02/06/20) K3.x
R7000P DD-WRT 40270M kongac
E4200 v1 FreshTomato 2020.1
E4200 v1 FreshTomato 2020.2.development
R7000 FreshTomato 2020.2.development
E4200 v1 1.0.07.development
WRT3200ACM OpenWRT 18.06.6
---------------------------------------------------------
Linux User #377467 counter.li.org / linuxcounter.net
TheCoder
DD-WRT Novice


Joined: 16 Feb 2020
Posts: 5

PostPosted: Mon Feb 17, 2020 10:41    Post subject: Reply with quote
Flashing with TFTP/Asus Restoration utiliy and CFE minivweb server gives the same result. They say that flashing is succesfull but the router bootloops. Only software that works is OpenWRT.
hebeda
DD-WRT User


Joined: 18 Sep 2006
Posts: 401
Location: Leipzig, Germany

PostPosted: Mon Feb 17, 2020 14:52    Post subject: Reply with quote
must clear nvram ram after flash , do that from asus emergency webinterface , otherwise the bootloop continues


and flash original firmware first - use old and smallest stockfirmware you can find, then clear nvram, then flash anythign else
TheCoder
DD-WRT Novice


Joined: 16 Feb 2020
Posts: 5

PostPosted: Mon Feb 17, 2020 14:55    Post subject: Reply with quote
I am clearing the NVRAM before and after the flashing. My problem is not common. Anytime I flash via serial and tftp a file larger than 15 mb it fails. Maybe something is wrong with the memory? Is it possible to format it via serial commands?
hebeda
DD-WRT User


Joined: 18 Sep 2006
Posts: 401
Location: Leipzig, Germany

PostPosted: Mon Feb 17, 2020 15:49    Post subject: Reply with quote
it can be a faulty flash, its rare but it happens , out of +200 routers ive upgraded last year to dd.wrt just one unit had a broken flash(was a netgear wndr4500v2 ).... detection of a broken flash memory can be time consuming.

but you should see that from serial console information, during flashing process it should give an error ...

that explains maybe , why you can use openwrt but nothing else ....

but you should see the cause for reboot, when you have a serial connection ....
kernel-panic69
DD-WRT Guru


Joined: 08 May 2018
Posts: 3410
Location: Texas, USA

PostPosted: Mon Feb 17, 2020 16:10    Post subject: Reply with quote
Break CFE boot. 'nvram erase'. Mini CFE webserver. At most, you may have to do flash via serial recovery as far as I know. I don't think RMerlin modified the CFE. I've recovered about a dozen of these over the past year, all still running. I don't see how your flash chip would've been messed up, unless you were using jffs2. If it's to that extreme of a point, then you need to figure out how to offset the flash partitions to compensate.
_________________
E4200 v1 DD-WRT 42287 mega (02/06/20) K3.x
R7000P DD-WRT 40270M kongac
E4200 v1 FreshTomato 2020.1
E4200 v1 FreshTomato 2020.2.development
R7000 FreshTomato 2020.2.development
E4200 v1 1.0.07.development
WRT3200ACM OpenWRT 18.06.6
---------------------------------------------------------
Linux User #377467 counter.li.org / linuxcounter.net
TheCoder
DD-WRT Novice


Joined: 16 Feb 2020
Posts: 5

PostPosted: Mon Feb 17, 2020 22:43    Post subject: Reply with quote
Thank you hebeda and kernel-panic69 for your commitment.

I haven't played with jtag/serial before. I haven't touched jffs2. I don't know if putting wrong firmware applies to this. I had allowed jffs commands because I have been using Diversion adblocker on Merlin.

CFE looks healthy to me.

There is no much helpful information in the boot but maybe you will find something useful:

Tomato bootloop (most detailed): https://pastebin.com/P88NRc5b

DDWRT is not bootlooping, just getting stuck in boot: https://pastebin.com/QcPB28jY

John's merlin boootloop: https://pastebin.com/1ayWdA7h

Official software bootloop: https://pastebin.com/ADcu8Kz7

I've tried to upload the softs via serial but also CFE. Of course, boot was preceded by an NVRAM erase.

When it comes to errors: asus firmare restoration, CFE webserver, don't give any error (they report succesfull flash). Only tftp flashing via serial is showing an error anytime it reaches approximately 15th megabyte. The error is misleading but maybe indicates another reason:

Code:
CFE> flash -noheader : flash1.trx
Reading ::
TFTP Server.
..tftp retry wait 0
break!! reach max retry!!
Failed.: I/O error
*** command status = -4


Do you see any errors in the boot that could help?


Are you able to help me with offsetting the partitions? Is it even possible via serial?


btw, here are my partitions:


Code:
CFE> show devices
Device Name          Description
-------------------  ---------------------------------------------------------
uart0                NS16550 UART at 0x18000300
uart1                NS16550 UART at 0x18000400
nflash0              AMD NAND flash size 131072KB
nflash0.boot         AMD NAND flash offset 0 size 512KB
nflash0.nvram        AMD NAND flash offset 80000 size 1536KB
nflash0.trx          AMD NAND flash offset 200000 size 1KB
nflash0.os           AMD NAND flash offset 20001C size 129024KB
nflash1.boot         AMD NAND flash offset 0 size 512KB
nflash1.nvram        AMD NAND flash offset 80000 size 1536KB
nflash1.trx          AMD NAND flash offset 200000 size 63488KB
nflash1.brcmnand     AMD NAND flash offset 4000000 size 65536KB
eth0                 Broadcom BCM47XX 10/100/1000 Mbps Ethernet Controller
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