How to find Correct Mikrotik RB750GR3 fw_env.config

Installing and Using OpenWrt
1

Hi,
I am trying to read u-boot env variables from rb750gr3

Device has original boot partitions and has original bootloader
so how can i find correct fw_env.config parameters for this device?
Thanks for help.

cat /proc/mtd 
dev:    size   erasesize  name
mtd0: 00040000 00010000 "RouterBoot"
mtd1: 0000f000 00010000 "bootloader1"
mtd2: 00001000 00010000 "hard_config"
mtd3: 0000f000 00010000 "bootloader2"
mtd4: 00001000 00010000 "soft_config"
mtd5: 00001000 00010000 "bios"
mtd6: 00fc0000 00010000 "firmware"
mtd7: 00270000 00010000 "kernel"
mtd8: 00d50000 00010000 "rootfs"
mtd9: 00ae0000 00010000 "rootfs_data"
2

The easiest way is to printenv from the bootloader's console. This is before you boot the device.

3

Thanks but this can't be a solution
mikrotik locks rb750gr3 bootloader access
and also locked serial lines

4

What are you looking for exactly?
MikroTik uses this: https://openwrt.org/toh/mikrotik/common#routerboard_configuration

1 Like
5

I have installed OpenWrt on it . There is no problem at this point.
But i want to read u-boot env variables like run fw_printenv and get u-boot env dumps like serial number, boot args etc.

for example

root@OpenWrt:~# fw_printenv 
bootcmd=tftp
bootdelay=5
baudrate=57600
ethaddr="XX:XX:XX:YY:YY:YY"
ethact=Eth0 (10/100-M)
serial#=123456789a
stdin=serial
stdout=serial
stderr=serial
ipaddr=192.168.16.123
serverip=192.168.16.112
bootfile=
root@OpenWrt:~#

this can be done with correct fw_env.config settings
for example there is incorrect parameters shown below

root@OpenWrt:~# cat /etc/fw_env.config 
# MTD device name       Device offset   Env. size       Flash sector size       Number of sectors
/dev/mtd1               0x0000          0x1000
6

If you did not replace RouterBoot with U-boot then there is no U-boot env and so the answer to your question is that there are no correct settings as it doesn't exist

3 Likes
7

Thanks, Okey I didn't installed U-Boot so there is no env .

Is there any method to build and install u-boot to rb750gr3 without using SPI Flash programmer?

8

Like I've said above,

 ls -1 /sys/firmware/mikrotik/hard_config
board_identifier
board_product_code
board_serial
booter_version
flash_info
hw_options
mac_base
mac_count
mem_size
product_name
wlan_data

 ls -1 /sys/firmware/mikrotik/soft_config
bios_version
boot_delay
boot_device
boot_key
boot_proto
booter
commit
cpu_mode
cpufreq_index
silent_boot
uart_speed
3 Likes
9

Thank you so much
I was looking for this exactly :grinning: :100:

10

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