RT-AXE7800 mcb load failed

[McKey]

Hi guys!

Anyone with idea what could be wrong with this router? (UART msg below) It stucks after the U-Boot SPL. Im im correct, that means it cant get the 2nd stage bootloader (u-boot) from the flash?
Also, anyone ever found explanation about the startup check, and what are they means? (Like USBT and UHD)
Regards.

----
BTRM
V3.0
MEM?
MEMP
CACH
DATA
ZBSS
MAIN
NAND
OTP?
OTPP
USBT
UHD?
UHDP
IMG?
IMGL
UBI?
UBIP
PASS
----

U-Boot SPL 2019.07 (Jun 08 2022 - 15:20:20 +0800)
Strap register: 0x7fffdf43
Board is non secure
$SPL: 5.04L.02@348603 $
nand flash device id 0xc2da9091, total size 256MB
block size 128KB, page size 2048 bytes, spare area 108 bytes
ECC BCH-8
FFinit done
find magic number 0x75456e76 at address 0x40000
CRC mismatch len = 16384
computed 7f6be855
expected ab0a667
no mcb specified explicitly, use safe mode
blob not found for magic 0xcb00cb sel 0x1607!
FFinit find magic number 0xcb00cb at address 0xa7000
reading blob from 0xa7000 offset 0x286c len 608
digest sha256 mismatch
mcb selector 0x1607 not found using  0x1607 instead
blob not found for magic 0xcb00cb sel 0x1607!
mcb load failed
### ERROR ### Please RESET the board ###

 

[McKey]

So. I figured it out. This message means that the code on the CPU flash (dunno wich CPU) are fine and cant read your corrupted external MXIC flash.
I got an another AXE7800 with a burnt CPU. I desoldered the MX30LF2G28AD flash from that one and i swapped that flash with the one with this problem above. And it runs. If you are out of warranty and get this same message above, order the MX flash chip above with an xGecu programmer and poke me for the AXE7800.BIN file. No need to thank for this, i already made some barbecue to celebrate myself.

 

[wangrp88]

I have exactly the same issue. Can you please send me the bin file? I will have to find the programmer...

 

[McKey]

Wrong news: You have to find a flash chip, with zero amount of bad blocks from the factory for this. I tried many methods to find a way to keep the original bad block table, but not a single one worked. I assume that both the chip and the OS are doing something with bad blocks, so only going to work, if you find one without bad blocks, and you flash that with the content of your original (or a working) flash dump. After that it will use the original chips bad block table, and the new bad blocks will be added to it. Otherwise, the real bad blocks on the new chip are going to be on a random place, and somehow they will be not registered as bad (or goes above the max limit of allowed bad block count) and the router will crash. Could crash even after a month. I purchased 20+ MXIC flashes, and only two of em had zero amount of bad blocks, so it is a silicon lottery. I would say not worth the hassle, unless you can sell the spare flashes with 1-2-8... amount of bad blocks from the factory.

 

[wangrp88]

Appreciate the info! I guess it does not worth the effort. Any other options to revive the router? Here is my serial console output:

U-Boot SPL 2019.07 (Jun 08 2022 - 15:20:20 +0800)
Strap register: 0x7fffdf43
Board is non secure
$SPL: 5.04L.02@348603 $
nand flash device id 0xc2da9091, total size 256MB
block size 128KB, page size 2048 bytes, spare area 108 bytes
ECC BCH-8
FFinit done
find magic number 0x75456e76 at address 0x40000
FFinit find magic number 0xcb00cb at address 0x45000
reading blob from 0x45000 offset 0x23ac len 608
digest sha256 mismatch
mcb selector 0x12143b not found using 0x1607 instead
blob not found for magic 0xcb00cb sel 0x1607!
mcb load failed
### ERROR ### Please RESET the board ###