Where there are multiple virtual interfaces, the wifi driver “rt28xx” only support minor (last 7 bit) change of the MAC address, compared to the permanent MAC address, which is loaded from flash when system start.
So you cannot change the MAC address freely when the wifi driver is loaded. The permanent MAC address is in mtd2. So if you compile your own firmware, you can keep this mtd partition unlocked. You can then change the mac address and write it back. Then reload the wifi driver.
It is already an improvement if it is possible to do minor changes to the MAC address that can cover some use cases, although some other cases are not covered as easily.
Some other thoughts:
If this is a driver limitation, would it not be theoretically possible to create a driver that changes this behavior (where it loads the MAC address from)? The question is if and how this could be done and how hard it is.
You say that is is possible to keep the mtd partition unlocked if we compile our own firmware. Why is it necessary to be locked in the first place? And wouldn't it be possible to create a firmware that unlocks it, changes the mac address and reload the driver in software only when it is needed (i.e. when one wants to change the MAC address)?
I am not sure if this is a limitation of the driver or required by the chips. But I believe it is the chips, otherwise it is easy to change the driver. I changed some codes of the driver so that you can change the mac address freely, but once the repeater is connected, all devices are rejected to connect to the ap. It means only the first VAP interface can work successfully.
Several mtd partition is locked, for example uboot, factory (radio data with MAC address) etc. The reason is to protect these data from changing in OpenWrt because they are sensitive. When you compile your own firmware, you can keep these mtd unlocked so that you can just change the data. So I think this is the only way to change mac address freely.
@theP, we cannot provide upgraded version for MT300A and MT300N so that you can change mac address freely. If you want to do this, please use AR150 or our coming AR300M.
Will you let us know here when a firmware with limited changing is available?
Can you give more information about the AR300M? I could not find it on the site. When will it be out?
Regarding the MT300A and MT300N: It may be a bit too much work for most people to compile the firmware. Maybe two binary versions could be made available for download?
Another possible solution: Wouldn’t it be also possible to only unlock the partition as needed for the interface to change the mac address ? Either a manual unlock/lock button or by just having the button that changes the mac perform a lock/relock after changing the mac address?
Regarding to MT300A/N, we have just updated the firmware v2.20, downloadable from http://www.gl-inet.com/firmware/testing/. The flash is unlocked so you can change the mac address. I still need sometime to write a secure script though. For most people, just don’t change the mac address. If you damage the data, you may never got wifi back. The script will do the following operations.
mtd unlock factory
#change the mac address
mtd lock facotory
AR300M is using Atheros chips, so you can just change the mac address freely. Production finished. We will put on web store soon.
In normal use, just don’t change mac address for MT300A/N because they are not supposed to do this.
I tried to clone the mac address with MT300-V2 (Mango v2) and it seems to work fine (Cable and Repeater). However to restore the original mac address (factory value) you have to write it manually in the GUI as it shows ff:ff:ff:ff:ff:ff which is not correct.
Anyway I would prefer an official confirmation for the availability of this feature with the new Mango.