TP-Link MR-3420 v2.x: ar71xx kernel for imagebuilder 18.x missing

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1

Hi!
I've read about some of the ar71xx issues and porting it to ath97, but I am not sure whether this answers my question as well - please forgive me, I am a noob on non-x86 hardware.

The mr-3420 build has been pretty difficult up until 17.x as space is really limited. I think this might have been the reason why its support got removed in 18.x. However, tweaking packages here and there, I have always been able to make it boot with usb support and outsource the rest.

I tried to do the same with 18.x
I re-added the target/profile in the make files and it seems the rootfs gets built properly. However, the kernel is missing:
make[3]: *** No rule to make target '/mnt/scratch/openwrt-imagebuilder-18.06.1-ar71xx-generic.Linux-x86_64/build_dir/target-mips_24kc_musl/linux-ar71xx_generic/tl-mr3420-v2-kernel.bin', needed by '/mnt/scratch/openwrt-imagebuilder-18.06.1-ar71xx-generic.Linux-x86_64/build_dir/target-mips_24kc_musl/linux-ar71xx_generic/tmp/openwrt-18.06.1-ar71xx-generic-tl-mr3420-v2-squashfs-sysupgrade.bin'. Stop.

Should I invest time in building the kernel myself (bonus question - is there a quick way/howto for just compiling the default kernel with default options for this target?) or will there be other, more grave issues kernel-wise?
Adding the average kernel size of 1,4M to my rootfs, I get 3409K which should totally be possible to fit on the router.

Thanks for any input and sorry again if I should just accept ar71xx is more or less considered dead.

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First of all, albeit a bit tiring, this is a real issue and becomes more and more of a problem: https://openwrt.org/supported_devices/432_warning

ath79 (using device tree and being merged mainline) is the successor of ar71xx (not using device tree but mach files instead, not mainline), covering exactly the same hardware in a slightly different -mainline acceptable- way. The point where ath79 becomes 'official' and ar71xx deprecated (no new device additions) is probably not too far away. On the one hand ath79 will save a little space (by using device tree, instead of compiling the mach file for all ar71xx devices statically into the kernel), on the other hand the kernel is getting bigger making 4/32 devices much harder to support at all (the jump from kernel 4.9 to 4.14 is really significant there). There is quite some activity of porting ar71xx to ath79 already, if you care about your tl-mr3420-v2, this would be a good opportunity to pick up.

But neither of those things are your actual problem here, due to software growing, tl-mr3420-v2 is no longer part of ar71xx/generic, but has been moved to the ar71xx/tiny subtarget instead - using its corresponding imagebuilder should get you started.

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