No /dev/mem on lede 17.01.2 build but ok with openwrt 15.05.1


I try to use this tool to disable mux for JTAG pin. : devmem
But I have no /dev/mem folder.

hardware : Ubiquity unify AP ( AR7241 + AR9287 )
firmware used : lede-17.01.2-ar71xx-generic-ubnt-unifi-squashfs.bin

If I install openwrt ( openwrt-15.05.1-ar71xx-generic-ubnt-unifi-squashfs.bin ) /dev/mem is present and I have access to memory via devmem or scripts !

I think an option is missing on the lede build.
I can build my own lede ( and openwrt ) firmware, but I don't know what to add to lede build !
I already tried to add these options with no success :
In kernel menuconfig, Device Drivers, Character devices : /dev/mem virtual device support and /dev/kmem/ virtual device support.

Can you help me ?

Thanks in advance

You could enable the CONFIG_KERNEL_DEVMEM=y symbol in your config file.
If you need /dev/kmem too, check CONFIG_KERNEL_DEVKMEM=y

This will enable the kernel symbol for /dev/mem.

1 Like

strange !

CONFIG_KERNEL_DEVMEM=y were present in the config file.
So I have removed the config and restarted from scratch and added manually this line and this is ok !