repair ac86u with delsolder flashing

[trewmdh3]

hi, i have desolder the rom chip from the motherboard of ac86u, where can i find the flash file for the chip?

 

[Hazel]

hi, i have desolder the rom chip from the motherboard of ac86u, where can i find the flash file for the chip?

No idea, but @Tech9 might be able to help you.

 

[Tech9]

I don't have a flash dump from this router. I was about to brick one AC86U intentionally to investigate another potential issue, but the router survived. My plan was to swap the chip from a donor board if the router bricks, but it wasn't necessary. Why did you de-solder the chip, @trewmdh3? Anything related to the thread below?

Accidentally flashed RT-AX86U firmware on RT-AC86U and now unable to flash back the correct firmware

Hi, I made the mistake flashing the firmware first thing after waking up and accidentally downloaded the AX86U release (RT-AX86U_386.2_4_cferom_pureubi.w) and flashed it via the ASUS Firmware Restoration tool by putting the router into recovery mode. Since then, I'm unable to put the router...

www.snbforums.com

 

[trewmdh3]

I don't have a flash dump from this router. I was about to brick one AC86U intentionally to investigate another potential issue, but the router survived. My plan was to swap the chip from a donor board if the router bricks, but it wasn't necessary. Why did you de-solder the chip, @trewmdh3? Anything related to the thread below?

Accidentally flashed RT-AX86U firmware on RT-AC86U and now unable to flash back the correct firmware

Hi, I made the mistake flashing the firmware first thing after waking up and accidentally downloaded the AX86U release (RT-AX86U_386.2_4_cferom_pureubi.w) and flashed it via the ASUS Firmware Restoration tool by putting the router into recovery mode. Since then, I'm unable to put the router...

www.snbforums.com

router was having endless restart after power on , i need to wait for hours for it to stop and become normal . i think there is something wrong with the firmware , maybe the flash chip is dying, i want to flash a new chip and solder to save it

 

[Tech9]

i think there is something wrong with the firmware

I don't think so. Software doesn't heal itself miraculously. Your router perhaps has a bad solder joint. There is a relatively quick way to tell without any special equipment. I'm assuming you have the PCB out of the shell. Heat up the back side with a hair dryer to about 70C. Does it boot now? This defect is non repairable, unless you have unlimited time to kill. I had one fixed temporary and it failed again in a week time.

 

[trewmdh3]

I don't think so. Software doesn't heal itself miraculously. Your router perhaps has a bad solder joint. There is a relatively quick way to tell without any special equipment. I'm assuming you have the PCB out of the shell. Heat up the back side with a hair dryer to about 70C. Does it boot now? This defect is non repairable, unless you have unlimited time to kill. I had one fixed temporary and it failed again in a week time.

no , it continue to boot loop

 

[vaboro]

router was having endless restart after power on

You may experience a boot loop due to kernel panic after a firmware update or a configuration change.
Are you connected to the router's UART interface?

 

[vaboro]

i think there is something wrong with the firmware , maybe the flash chip is dying

For how long have you been using the device? What are the ambient operating conditions and internal chip temperatures? Do you often power if off and then on again or does it usually stay always on?

 

[trewmdh3]

For how long have you been using the device? What are the ambient operating conditions and internal chip temperatures? Do you often power if off and then on again or does it usually stay always on?

less than 7 days, ambient 27C, it works at 60-70C ,i power off and on often. i have used asus firmware restoration , still boot loop. what should i do when i connect the UART interface

 

[vaboro]

less than 7 days, ambient 27C, it works at 60-70C ,i power off and on often

Then it's very unlikely that your router has a bad solder joint. Bad solder joints develop over the years of operating at high/extreme internal chip temperatures, low ambient temperatures and turning the device on and off often. But even if bad solder joints develop (happens from time to time with GPU chips) reballing the chip solves the problem.

i have used asus firmware restoration , still boot loop

Asus firmware restoration doesn't always solve the boot loop problem. You may try resetting nvram, see this post: http://www.snbforums.com/threads/rt-ac86u-random-crash.72031/

what should i do when i connect the UART interface

First off all you will diagnose the problem. Kernel panic reveals itself like this:

Kernel panic - not syncing: Fatal exception
CPU0: stopping
CPU: 0 PID: 0 Comm: swapper/0 Tainted: P      D         4.1.27 #2
Hardware name: Broadcom-v8A (DT)
Call trace:
[<ffffffc0000876d8>] dump_backtrace+0x0/0x150
[<ffffffc00008783c>] show_stack+0x14/0x20
[<ffffffc0004fec24>] dump_stack+0x90/0xb0
[<ffffffc00008e730>] handle_IPI+0x190/0x1a0
[<ffffffc000080c70>] gic_handle_irq+0x88/0x90
Exception stack(0xffffffc0006d3d80 to 0xffffffc0006d3ea0)
3d80: ade8a830 00000004 1ffd92f0 ffffffc0 006d3ec0 ffffffc0 0036ba0c ffffffc0
3da0: ade8a830 00000004 10000000 00106f2f 000bfeb4 00000000 14000000 00000000
3dc0: 00000b50 00000000 00000018 00000000 00000000 000f7f49 1e8a1528 ffffffc0
3de0: 006e2460 ffffffc0 ffff9247 00000000 00512803 ffffffc0 191d4d70 ffffffc0
3e00: 00512828 ffffffc0 175a58c0 ffffffc0 175a5668 ffffffc0 000006c8 00000000
3e20: 00000012 00000000 00000000 00000000 00000000 00000000 ade8a830 00000004
3e40: 1ffd92f0 ffffffc0 00000001 00000000 00000001 00000000 ad751c94 00000004
3e60: 006cc2e8 ffffffc0 00707588 ffffffc0 0050d000 ffffffc0 006d0000 ffffffc0
3e80: 006cd000 ffffffc0 006d3ec0 ffffffc0 0036ba04 ffffffc0 006d3ec0 ffffffc0
[<ffffffc000083da8>] el1_irq+0x68/0xd8
[<ffffffc00036bb10>] cpuidle_enter+0x18/0x20
[<ffffffc0000c68f0>] cpu_startup_entry+0x1e8/0x250
[<ffffffc0004f9bc0>] rest_init+0x88/0x98
[<ffffffc000696970>] start_kernel+0x394/0x3a8
crashLogCommit: write 1 blocks  data_offset 131072
Rebooting in 3 seconds..

If you see something like this on the console then the above method should help.

 

[Tech9]

less than 7 days, ambient 27C, it works at 60-70C ,i power off and on often. i have used asus firmware restoration , still boot loop.

I don't understand well what's goin on here. A router used for 7 days only and you decided to open it and remove the flash chip - really? More details on what exactly firmware you uploaded and how you did it may eventually help. Did you flash a wrong firmware on that router?