ASUS AX4200 bootloop after upgraded from 23.05.4 to snapshot build

If possible we should find a work-around which doesn't require patching the kernel. Carrying kernel patches which are impossible to be included upstream (for good reasons) is a burden for the project and makes maintaining our source tree the harder the more of those out-of-tree hacks exist. A single device with a new bootloader version doesn't justify adding such patches.

I suggest to downgrade U-Boot to the version from 2022 before commit 36fee2f7621 as there is no advantage of using a newer U-Boot version with OpenWrt.

Very bad decision. And you didn't see the full scale of the problem.

This issue is not limited to one device.
There is already a device from Asus on the market that has the bootloader version 2022.10 installed (the specified patch is already included):

Proof: ASUS AX-1800S V2 (not RT-AX54) cant't flash with bootloader ver 2.0.0
I have already compiled OpenWrt 23.05.4 for RT-AX57M, but on the snapshot I will encounter the same problem.

And every day there will be more and more devices in which Uboot is installed with the specified fix (commit 36fee2f) and the presence of a common UBI partition.

At the moment, the issue is related to the following devices:

ASUS RT-AX52
ASUS RT-AX57M
ASUS RT-AX59U
ASUS TUF-AX4200
ASUS TUF-AX6000

The issue reported will likely affect the following devices:

ASUS RT-AX89X
OpenWrt One (of course there is a custom bootloader here)
mercusys,mr90x-v1
tplink,re6000xd
cellc,rtl30vw
teltonika,rutx10 
teltonika,rutx50 
zte,mf18a 
zte,mf282plus 
zte,mf286d 
zte,mf287 
zte,mf287plus 
zte,mf287pro 
zte,mf289f 
platform bcm4908 

There is a similar problem on the qcom platform (ipq80xx) and it is also solved by deceiving the logic of Uboot.
Example:

And here all hope is that the logic of the Uboot operation will remain the same (and there is a flaw in the logic).
Personally, I really don’t like such decisions (which are based on hope).

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Hi, is it possible to download this file "asus_tuf-ax4200-ubi-cleaner.trx" somewhere? I have a similar issue with ASUS TUF-AX4200 now. I followed this steps Asus TUF AX4200 support - #241 by remittor (Using Web Interface) - everything was fine and OpenWrt 23.05.5 was running fine. Then I downloaded "asus_tuf-ax4200-squashfs-sysupgrade.bin (24.10.0-rc1)", upgraded it via LuCi and that's when the bootloop started. I also tried "ASUS Firmware Restoration tool" but it didn't help. Thanks for the help.

https://drive.google.com/drive/folders/1c10G1LZuTiCo8dOItq3FV6A3-XK7-QfV

I have already started building OpenWrt 24 for Asus routers.
I will post fixed OpenWrt 24.10.0-rc2 it there today or tomorrow.

FYI: A rather simple method to downgrade the bootloader (and get out of the bootloop) is using the Asus firmware restoration tool. At least unless Asus comes up with a new HW rev where this might lead to a brick.

Working bootloader trx and bin files (the latter for flashing via TFTP) are included in the 3.0.0.4.388_33147 GPL source code from the Asus support website:
https://dlcdnets.asus.com/pub/ASUS/wireless/TUF-AX4200/GPL_TUF_AX4200_300438833147.zip?model=TUF-AX4200

You can find the u-boot_nand_202308021202_v1004_tuf-ax4200_ddr3.trx file a bit hidden in the asuswrt/release/src-mtk-MT798X/.bin/DEFAULT in the tgz inside the zip.

Downgrading the bootloader using the restoration tool and also via TFTP worked fine here with two AX4200 that a bought a few weeks ago.

But, of course, it would be better if stock OpenWrt could work well with the newer U-Boot version / bootloader - flashing bootloaders is always a bit risky, so you have been warned.

so long,

Hias

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New bootloaders may add support for new NAND chip (storages)!
So you can get a hard brick in this case.

Sure, this is only safe on devices that originally came with 1.0.0.4 bootloader / U-Boot 2022.04-rc1 or earlier. Don't try this unless you are 100% sure.

I bought a total of 3 AX4200 last month from Amazon and they still seem to ship with the 1.0.0.4 bootloader (I verified that on two of the devices, on the other one I performed an Asus firmware update before installing OpenWrt and couldn't verify the bootloader version - but very likely it was also 1.0.0.4 and the downgrade worked). Of course, this can change any time or could already have changed - only Asus would know.

so long,

Hias

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