2019.1 kernel won't boot from eMMC (Asus C100PA)

[commradd]

I have an Asus C100PA that boots the latest veyron image from USB just fine, even from a micro SD, but not from the internal 16 Gig eMMC drive. I dd'd the image directly from USB to the eMMC, and all I get after booting is a black screen with a backlight. Normally, if the device doesn't find bootable media, the UEFI will beep at me, but not in this case, which indicates that it attempts to boot the kernel. Unfortunately, this kernel build seems to be rather quiet, and even after changing the cmdline and repacking, debug doesn't give me any more information.

I have previously ran the 3.14 kernel without issues. If I dd a working 3.14 installation to the eMMC, it boots and works fine. If i just dd the 4.19 kernel (sda1) to the eMMC (mmcblk0p1), it won't boot either. I would expect this not to work entirely as I'm using the wrong modules at this point, but I should still see kernel errors I would think.

Any ideas what might be preventing me from booting from eMMC? I'm sure it's probably something simple, but i'm running out of options. Just for kicks, I recompiled the kali 4.19 kernel with the same config (a few changes here and there), and still no luck. Just a black screen...

Thanks

[steev]

That's a good question as to why it won't work. What did you change the command line to add? You may need to go through and build the graphics into the kernel, I believe I have them as a module (more because future planning of using the same image for veyron/nyan/exynos chrome books although building the graphics into the kernel shouldn't do anything bad across the 3, just increase the kernel size) so it's loading (or not loading) early enough for it. The option, iirc is CONFIG_DRM_ROCKCHIP.

You'd also want to pass something like "console=ttyS2,115200n8 earlyprintk=ttyS2,115200n8 console=tty1" into the kernel. I have not attempted to image the Chromebook to eMMC though as I only have the 1, and I haven't worked out a great way for the onscreen keyboard to work when in tablet mode.