Generic-lpae unbootable on raspberry pi 3

[Adam Smith]

I've been trying to boot the generic-lpae kernel on my pi 3B. I've tried via U-boot and the pi's built in bootloader, but without success. There seems to be something inherently missing from the kernel. There are no bcm dtb files under armhf, but they are there for arm64. Using the one from arm64 with generic-lpae still fails to boot.

Without the use of generic-lpae it is very hard to use the mini/netboot installer. It also means there is no hardware enablement stack on raspberry pi.

Debian has had the ability to boot generic-lpae on the pi2 since 2015 I think!

[Paolo Pisati (p-pisati)]

We have a kernel dedicated to the RaspberryPi boards (linux-raspi2), why do you want to use the generic-lpae kernel instead?

Besides, you can't mix dtb and kernels from different arches / branches - they won't work together.

Someone mentioned that it was able to install the generic arm64 server img on RaspberryPi, you might give that a try.

[Adam Smith (adamsmith)]

Yes I wrote the instructions on the raspberry pi wiki about how to boot arm64. But I'm not talking about that here.

Raspberry pi is now supposedly fully supported in the Linux kernel - https://www.omgubuntu.co.uk/2018/08/linux-4-18-kernel-release-features - but I don't want to have to go through the pain of compiling this.

I would like generic-lpae support for the reasons I outlined in the first post. Currently Ubuntu only provides one install media for the pi which is the server image (which doesn't work on the pi3 anyway).

I would like to get armhf fully working (or closer to) in the debian-installer/ubiquity. I'm willing to work on patches, but I only have a pi3 to work with.

It is also very hard to get changes/patches accepted in raspi2 packages. Generic-lpae seems better supported.

[Adam Smith (adamsmith)]

This https://ubuntu-mate.community/t/aarch64-on-raspberry-pi-2-rev-1-2-3b-3b/16853/37 is currently what you have to do to use the armhf netboot installer on a pi 2/3B/3B+. The debian-installer has no knowledge of the raspi2 kernel (you can't force it to install it), nor does raspi2 have any udebs.

I want to try grub2 on armhf, but I can't with raspi2 because it doesn't have the right modules built in. I've had a bug raised on that for months.

Supposedly 5 million 3B+ have been sold since March. That is a lot of potential Ubuntu users. However Ubuntu hasn't updated the firmware for well over a year and a half to allow the 3B+ to boot, nor has it added a flash-kernel database entry for the 3B+.

U-boot used on the server image doesn't work with the 3B or 3B+.

It's great that Ubuntu provides raspi2, but it doesn't actually provide any suitable media to install Ubuntu on the raspberry pi 3B/3B+.

With aarch64 on raspberry pi you have the arm64 kernel and the 64 bit version of raspi2. I don't see why there can't be generic-lpae and raspi2 for 32 bit.

Finally, the vc4 graphics driver is being continually updated and being stuck on the same kernel version is a pain. It would be great to be able to use the hw enablement stack kernels. They are generic-lpae.