Archer C6 v3 (as well as A6 v3) doesn't boot with Linux 5.10 (ramips/mt7621)

For Developers
1

Continuing the discussion from Possible Kernel 5.10 regression issue with MT7621 and SW/HW offload enabled:

This might resolve it:

diff --git a/target/linux/ramips/image/mt7621.mk b/target/linux/ramips/image/mt7621.mk
index b125df48d9..4e5411e917 100644
--- a/target/linux/ramips/image/mt7621.mk
+++ b/target/linux/ramips/image/mt7621.mk
@@ -1444,12 +1444,12 @@ TARGET_DEVICES += tplink_archer-a6-v3
 define Device/tplink_archer-c6-v3
   $(Device/dsa-migration)
   $(Device/tplink-safeloader)
+  $(Device/uimage-lzma-loader)
   DEVICE_MODEL := Archer C6
   DEVICE_VARIANT := V3
   DEVICE_PACKAGES := kmod-mt7603 kmod-mt7615e \
        kmod-mt7663-firmware-ap
   TPLINK_BOARD_ID := ARCHER-C6-V3
-  KERNEL := $(KERNEL_DTB) | uImage lzma
   IMAGE_SIZE := 15744k
 endef
 TARGET_DEVICES += tplink_archer-c6-v3

@dsouza please apply the patch above and try if that fixes the issue.

2 Likes
2

So sounds like those should be pulled for those devices until it's resolved.

3

I just tried a new build (mt7621.mk changed per below) on one of my Access Points.

After sysupgrade unfortunately the device is bricked again. I did this remotely (I am not at home right now), so it will be a while (possibly on Wednesday) until I can have physical access to connect a UART and de-brick it.

(...)
define Device/tplink_archer-c6-v3
  $(Device/dsa-migration)
  $(Device/tplink-safeloader)
  $(Device/uimage-lzma-loader)
  DEVICE_MODEL := Archer C6
  DEVICE_VARIANT := V3
  DEVICE_PACKAGES := kmod-mt7603 kmod-mt7615e \
        kmod-mt7663-firmware-ap
  TPLINK_BOARD_ID := ARCHER-C6-V3
  IMAGE_SIZE := 15744k
endef
TARGET_DEVICES += tplink_archer-c6-v3
(...)

EDIT 1: I am using a fresh build I did from master's head. I tried to apply your patch (using git apply and patch commands) but I got an error and I edited it manually (sorry, I'm not very skilled with diff/patch commands).

EDIT 2: below is the error I got when trying to apply your patch, that's why I manually edited the file.

dsouza@naspc:~/src/openwrt/master$ git apply mt7621.patch
error: patch failed: target/linux/ramips/image/mt7621.mk:1444
error: target/linux/ramips/image/mt7621.mk: patch does not apply

EDIT 3: git apply --ignore-space-change --ignore-whitespace mt7621.patch worked. Anyway the result is the same as I manually edited above, so it will not change the outcome (device does not boot and hangs while loading kernel with no error).

4

I guess we'll need to wait until you can show serial output of what's happening...

5

Previous snapthot builds with Kernel 5.10.92 (such as from Jan 19th - r18614-46ce629fe0) booted OK.

There might me something else commited after this date that is causing kernel fail to boot (any new kernel patch applied?)

6

As that's very recent, git bisect over kernel sources to find the culprit should be doable.

7

Another brick...

Why not just remove access so a proper bisect can be done?

1 Like
8

Following another thread, I also report that snapshot from Feb 1 08:33 bricks a Netgear R6220. I don't have a serial link to log, but as the power LED is not even blinking, I assume it means that the Kernel is not loading.

9

Reporting for Archer C6U, same.
Why the recoveries cannot be triggered though? C6U apparently has a recovery webpage which boots up if the kernel cannot be loaded properly. But even that is not launching. Does anybody know if C6U has tftp? There is not traffic on any ports in any key combination as far as I have tried.

10

@daniel, below is the UART output. It's the same thing as before (stuck at "Starting kernel ..."):

U-Boot 1.1.3 (May 13 2020 - 19:39:06)

Board: Ralink APSoC DRAM:  128 MB
relocate_code Pointer at: 87f58000

Config XHCI 40M PLL
flash manufacture id: ef, device id 40 18
find flash: W25Q128BV
*** Warning - bad CRC, using default environment

============================================
Ralink UBoot Version: 5.0.0.0
--------------------------------------------
ASIC MT7621A DualCore (MAC to MT7530 Mode)
DRAM_CONF_FROM: Auto-Detection
DRAM_TYPE: DDR3
DRAM bus: 16 bit
Xtal Mode=3 OCP Ratio=1/3
Flash component: SPI Flash
Date:May 13 2020  Time:19:39:06
============================================
THIS IS uboot
icache: sets:256, ways:4, linesz:32 ,total:32768
dcache: sets:256, ways:4, linesz:32 ,total:32768

 ##### The CPU freq = 880 MHZ ####
 estimate memory size =128 Mbytes

Press '4' or 't' to break the booting process

Press 'x' to enter recovery web server                                                     0
nm_init:791
nm_initFwupPtnStruct:276
nm_lib_readPtnTable:738
[NM_Debug](nm_lib_readPtnTable) 00743: NM_PTN_TABLE_BASE = 0xfe0000
[NM_Debug](nm_lib_readPtnFromNvram) 00569: partition_used_len = 1054, requried len = 8192
[NM_Debug](nm_lib_readPtnTable) 00751: Reading Partition Table from NVRAM ... OK

[NM_Debug](nm_lib_readPtnTable) 00759: Parsing Partition Table ... OK

[NM_Debug](nm_lib_readPtnFromNvram) 00569: partition_used_len = 2, requried len = 2
factory boot check integer ok.


3: System Boot system code via Flash.
## Booting image at bc040000 ...
   Image Name:   MIPS OpenWrt Linux-5.10.92
   Image Type:   MIPS Linux Kernel Image (uncompressed)
   Data Size:    2566268 Bytes =  2.4 MB
   Load Address: 82000000
   Entry Point:  82000000
   Verifying Checksum ... OK
data copied to 0x82000000
OK
No initrd
## Transferring control to Linux (at address 82000000) ...
## Giving linux memsize in MB, 128

Starting kernel ...
11

@subhranil, let's continue the unbricking discussion in the topic below. I will reply to you there:

12

Is there any evidence this issue is being experienced on other MT7621 devices?

13

Another brick here with 1feb snapshot on redmi ac2100 (mt7621).

2 Likes
14

Netgear R6220 also as reported above by @badulesia

1 Like
15

Yes, on Netgear R6220 for example.
"We're doomed"

16

https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=cd6a6e3030ff9b758469cc159c219bc7a49df5e8

3 Likes
17

I just did a new build from master's head and tested with an Archer C6 v3.2.

It is now booting OK, problem solved, thank you!!!!

U-Boot 1.1.3 (May 13 2020 - 19:39:06)

Board: Ralink APSoC DRAM:  128 MB
relocate_code Pointer at: 87f58000

Config XHCI 40M PLL
******************************
Software System Reset Occurred
******************************
flash manufacture id: ef, device id 40 18
find flash: W25Q128BV
*** Warning - bad CRC, using default environment

============================================
Ralink UBoot Version: 5.0.0.0
--------------------------------------------
ASIC MT7621A DualCore (MAC to MT7530 Mode)
DRAM_CONF_FROM: Auto-Detection
DRAM_TYPE: DDR3
DRAM bus: 16 bit
Xtal Mode=3 OCP Ratio=1/3
Flash component: SPI Flash
Date:May 13 2020  Time:19:39:06
============================================
THIS IS uboot
icache: sets:256, ways:4, linesz:32 ,total:32768
dcache: sets:256, ways:4, linesz:32 ,total:32768

 ##### The CPU freq = 880 MHZ ####
 estimate memory size =128 Mbytes

Press '4' or 't' to break the booting process

Press 'x' to enter recovery web server                                                                                        0
nm_init:791
nm_initFwupPtnStruct:276
nm_lib_readPtnTable:738
[NM_Debug](nm_lib_readPtnTable) 00743: NM_PTN_TABLE_BASE = 0xfe0000
[NM_Debug](nm_lib_readPtnFromNvram) 00569: partition_used_len = 1054, requried len = 8192
[NM_Debug](nm_lib_readPtnTable) 00751: Reading Partition Table from NVRAM ... OK

[NM_Debug](nm_lib_readPtnTable) 00759: Parsing Partition Table ... OK

[NM_Debug](nm_lib_readPtnFromNvram) 00569: partition_used_len = 2, requried len = 2
factory boot check integer ok.


3: System Boot system code via Flash.
## Booting image at bc040000 ...
   Image Name:   MIPS OpenWrt Linux-5.10.96
   Image Type:   MIPS Linux Kernel Image (lzma compressed)
   Data Size:    2581459 Bytes =  2.5 MB
   Load Address: 80001000
   Entry Point:  80001000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK
No initrd
## Transferring control to Linux (at address 80001000) ...
## Giving linux memsize in MB, 128

Starting kernel ...

[    0.000000] Linux version 5.10.96 (dsouza@dme300) (mipsel-openwrt-linux-musl-gcc (OpenWrt GCC 11.2.0 r18710-dc2da6a233) 11.2.0, GNU ld (GNU Binutils) 2.37) #0 SMP Tue Feb 1 23:34:07 2022
[    0.000000] SoC Type: MediaTek MT7621 ver:1 eco:3
[    0.000000] printk: bootconsole [early0] enabled
[    0.000000] CPU0 revision is: 0001992f (MIPS 1004Kc)
[    0.000000] MIPS: machine is TP-Link Archer C6 v3
(...)
18

OpenWrt SNAPSHOT r18711-4367d4f869 (Kernel 5.10.96) also running on Netgear R6220.

1 Like
19

Firstly, I'm really sorry that my commit bricked your routers.
I've fixed the root cause in 09f383465e07 and pushed the problematic patch again in 37753f34ac68. I've checked that this time the patch does not affect the other devices anymore, but I'd feel more relieved if you guys can check this on your routers.

3 Likes
20

Thank you. Checked with Archer C6 v3.2, it’s booting OK now!

2 Likes