Clarification about the problem in installing OpenWRT on ERX

[doremifajb]

Hello. I read "README" and I didn't understand the problem. Is it about newer hardware version of ERX, that does not take openwrt-ramips-mt7621-ubnt-erx-initramfs-factory.tar , or is it about something else? I think mainly I didn't understand what "The new distribution build" means. From the context it looks like it's talking about the file for OpenWRT (having only .bin file instead of .tar), but then 19.07.2 is an old thing, so I didn't understand what the problem with "new" thing..... I still have openwrt-ramips-mt7621-ubnt-erx-initramfs-factory.tar saved in my laptop. Is it still usable? Can I buy a new ERX and use this file to flash OpenWRT, or should I look for a used ERX to ensure that it's not the latest model? I am sorry for an ignorant question....

[stman]

The problem is simple :

The new versions of OpenWRT, when compiled, are too big in terms of binary image file generated by the compiler to be "installable" by Ubiquiti's OS, because the partionning of the flash cannot permit that when doing it from ubiquiti OS.

There is a security in the compilation process, if the image is too big, bigger than the partition size, then the compiling process refuses to generate the ad-hoc "tar" file, and instead, it generates a "bin" file which is not usable to install OpenWRT from ubuquiti's original OS.

The work arround consists in generating a smaller image, desactivating many options, and then install this reduced version from ubiquiti's OS.

Once ubuquiti's OS is replaced with this small image of OpenWRT, it then possible to upgrade to a normal image, because the limitation due to partition size with ubiquiti's OS is not present when OpenWRT already runs.

In the end, the installation process is done in two steps :

First, we installed the small OpenWRT image, on top of Ubiquiti's original OS, Then we upgrade to a full OpenWRT image, on top of the small OpenWRT image.

I hope these explanations will help you to understand what was the issue there.

Don't hesitate to ask me more questions if you have issues with the process, I know it by heart now, and will be able to help you in any situation or problem you could face with ERX routers and OpenWRT.

[doremifajb]

Thank you for your reply ! But I still don't understand. OpenWRT 19.07.2 is an old OpenWRT. So why is it a problem that newer versions of OpenWRT don't have .tar file? We need newer versions only for sysugrade, but that's done through OpenWRT 19.07.2, then it's OK if it's .bin file.

And in any case, am I correct that I can still use .tar file saved in my computer to flash ERX through Stock Firmware's GUI ? I do the following:

1. upgrade the stock firmware
2. upload openwrt 19.07.2 using the gui of the stock firmware.
3. sysupgrade with a newer version with .bin.

and it always worked.... and I don't see why it has anything to do with nonexistence of .tar file for newer openwrt.

[doremifajb]

Now I finally understood what my confusion was. The tar file I always use is the custom file you made, identical to the tar file you have on-line. That's why it works. I didn't realize that this "warning" was up there already, as I got the tar file. (It must be mid November). So nothing has changed, it should work then. Sorry for my confusion !

[boemekeld]

I'm lost and almost using a hammer to stop wasting time with this.

I can connect via Serial and also via SSH. The OpenWRT boot seems to be working, but it doesn't open the web interface.

[doremifajb]

The firmware you flash using the image openwrt-ramips-mt7621-ubnt-erx-initramfs-factory.tar doesn't have LUCI. Isn't it where you are at? You have to scp a new image with luci and install it. Then it works fine.... at least it worked for me.

[boemekeld]

Yes, exactly that. It works now! Thank you.