Hi,
I just recently managed to build a custom firmware for my RUT955. I am trying to remove stuff I don't need from my official firmware as I need a bit more space for the binary I plan on running on the device.
So far I managed to get the build running and it's producing two files in the `bin/ar71xx/tltFws` directory:
RUT9XX_R_GPL_00.06.07.5_UBOOT_3.2.6_MASTER_STENDUI.bin and RUT9XX_R_GPL_00.06.07.5_WEBUI.bin
So if I use the RUT9XX_R_GPL_00.06.07.5_WEBUI.bin in the normal WebUi, the recovery WebUi or on the box using `mtd` it seems to generally work, but the box doesn't boot because it encounters a kernel panic when trying to mount the root file system:
***************************************
* U-Boot 3.2.6 2020-04-14 *
***************************************
BOARD: Teltonika RUT9XX
RAM: 128 MB DDR2 32-bit CL3-4-4-10
FLASH: 16 MB Unknown XT25F128B
CLOCKS: CPU/RAM/AHB/SPI/REF
550/380/253/ 25/ 40 MHz
Hit any key to stop booting: 0
Booting image from 0x9F040000...
Vendor/image name: Teltonika RUT9xx
Hardware ID: 0x35000001
Whole image size: 15.5 MB (16252928 bytes)
Kernel size: 1 MB (1098572 bytes)
Rootfs size: 8.7 MB (9154098 bytes)
Kernel load address: 0x80060000
Kernel entry point: 0x80060000
Header CRC... skipped
Data CRC... skipped
Stopping network... OK!
Uncompressing Kernel... OK!
Starting kernel...
[ 0.000000] Linux version 3.18.44 (cdutz@ChrisXPS) (gcc version 4.8.3 (OpenWrt/Linaro GCC 4.8-2014.04 unknown) ) #1 Sun May 2 16:22:16 CEST 2021
[ 0.000000] bootconsole [early0] enabled
[ 0.000000] CPU0 revision is: 0001974c (MIPS 74Kc)
[ 0.000000] SoC: Atheros AR9344 rev 3
[ 0.000000] Determined physical RAM map:
[ 0.000000] memory: 08000000 @ 00000000 (usable)
[ 1.750000] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,4)
[ 1.750000] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,4)
So it seems to be missing something ... now I can see the RUT9XX_R_GPL_00.06.07.5_UBOOT_3.2.6_MASTER_STENDUI.bin is bigger and according to `binwalk` it contains more segments. Unfortunately the file is too big for the web-based update and I'm a bit hesitant to put the file on a usb stick and run it on the device itself as I'm afraid that I might irrecoverably brick the device if something goes wrong flashing the U-Boot part of the system.
Another thing is, if I copy the bin to a USB stick, mount that on the device and use `sysupgrade` on the device it claims to have finished flashing (which sort of only takes a fraction of a second) and then it reboots. However the system comes back with an unchanged firmware.
So not quite sure what to do to get my custom firmware running. Help greatly appreciated :)