Modifying Huawei B593u firmware images using FMK

Nothing special here in my opionion, but I've seen few comments saying that FMK doesn't work with Huawei B593u. Just follow instructions below and you end up with normal firmware image having one important difference - you can telnet in as admin from LAN side of device.

Unpacking Huawei B593u compressed Broadcom CFE bootloader

Sorry, one more B593u post but felt this is worth documenting.

While hacking my way into Huawei B593u I had big problem with Huawei crippled CFE bootloader. It was not talking to me and when I finally did get it to talk to me it was only one way. All I could see was CFE> prompt after smashing ^C but nothing else.

Differences of Huawei B593u and B593s

I got few B593u models and it's pretty straight forward Broadcom BCM5358 based router with Linux. As usual GPL sources were never published by Huawei crooks. LTE modem side is simply Qualcomm MDM9200 based Huawei USB dongle connected internally to Broadcom SoC over USB.

What's inside Huawei B593u-12 LTE router?

There ain't many pictures showing innards of B593u around and even less ones with any details. This obviously needs to be fixed.

Well, that was easy

I think ethernet switch and wireless aren't supported by opensource drivers so even with OpenWrt booting on Huawei B593u-12 it's not much use. USB connected LTE module is not detected, my guess is that some GPIO needs to be toggled to enable it. PCA9555 GPIO expander would need some work too. Also 256MB NAND-flash is missing, only 16MB SPI flash is found.

Teaser on Huawei B539u hacking

CFE> boot -elf -tftp 192.168.1.100:openwrt-brcm47xx-mips74k-vmlinux.elf