I found the issue I had when using the nyan-big_defconfig for kernel compilation.
CONFIG_USB_XHCI_HCD and CONFIG_USB_XHCI_TEGRA were missing and CONFIG_USB_XHCI_TEGRA must be a module, because otherwise firmware loading fails, since the firmware is not compiled into the kernel.
I've compiled a working 4.20.2 kernel with this minimal config:
https://github.com/reey/PKGBUILDs/releases/tag/v4.20.2
At the moment I'm working on a uboot PKGBUILD for nyan-big, sources can be found here:
https://github.com/reey/PKGBUILDs/tree/ ... t-nyan-big
U-boot is working with this, but I need to include the extlinux.conf, so archlinux is not booting up with this at the moment.
The script in boot.txt does not seem to work, I think the bootz command is not working in uboot for some reason..
My plan in the future is to change the linux-nyan package, so that it will allow to have multiple kernel versions installed at once and with each installation of a kernel a boot entry will be added to the extlinux.conf.
I'm not sure if this will work, but we will see
Also I sent the patches for u-boot to the mailing list yesterday.