[fabriciogcbh]

Hello everyone,

I have an old ZCOM TG2521 router. A few years ago I installed dd-wrt on it and it worked fine but the USB didn't work. It had been stored for a long time, as I needed a solution for a temporary project, remember this device, but I needed the USB. (It's the only one with USB available that I have).

I updated to the latest version of dd-wrt available and the USB didn't work.

So I thought I would see something parallel to solve the problem.

I found another model with the same processor, NIC, RAM and Flash memory. AIP-W502U, WRT160NL, E2100L.

I connected the serial to the device's board and downloaded as much information as I could.

One mistake I made was not trying to save the Flash before trying to change things.

I tried to download the wrt160nl version via serial, but nothing would make it work. When I restarted the device, the previous dd-wrt for tg2521 would start. I tried several times until I got tired. I entered a memory address incorrectly and ended up burning it over U-Boot (RedBoot) and ended up killing the device. Now the saga begins... After confirming the error and the device not turning on anymore, I removed the memory chip and started burning it manually. End of story: none of the bootloaders I found on the internet or compiled worked on the device. I believe I have the necessary memory addresses to try to restore the device. I compiled several versions of U-Boot and nothing. The original version was 1.0.2.0. I downloaded this version from git, but there is no reference in the code for its processor or board, AP81, AR7100. (old version doesn't have implementation of make menuconfig, and in the version that does have implementation, they removed the board, the oldest is the AP121). I don't understand much about this kernel structure to try to assemble the defconfig for the AP81 (I don't even know if it would be worth the effort for this construction). In the latest version of U-Boot I tried something generic, but without success. I couldn't get U-Boot in docker to make the process easier.

I tried to compile DD-WRT, without success, the old versions require an svn structure, toolchain and some other libs that I couldn't find or couldn't be used in my Debian 11 x64 distribution.

I tried to compile OpenWRT, also without success, but I found a docker that solved the compilation problem, but it didn't have the exact specifications for my device (openwrt doesn't actually have a compilation for the tg2521). This docker had the entire structure ready for the WRT160NL, I managed to compile it. I burned U-Boot onto the flash drive, burned the .bin file, and the device still didn't respond.

I tried to assemble the basic structure in qemu-system-mips with the files I compiled and the ones I copied from the internet, but none of them worked. I managed to get a ready-made compilation from some people, and qemu worked, at least to confirm that it was ok.

After reading a few things about it, it seems to me that I have to assemble a small U-Boot + kernel + memory addressing structure in an image using mkimage to burn this file directly onto the flash drive. There is a lack of documentation and the documentation that does exist is not clear enough for me to understand the process.

I just wanted to try to make the USB work, now I'm trying to get the device back to life, if the USB doesn't have a solution, at least to make the device functional again.

Someone with enough experience in the subject could give me the correct path, or provide me with the bootloader file so I can keep trying something, or a copy of the models listed above for a last attempt. Compatible models: TG2521, Alfa Networks AIP-W502U, Linksys WRT160NL, E2100L.

I tried chat-gpt, gemini, copilot. None of them were able to give me valid instructions to be successful.

Below is the log of the technical information I have about the device.