Hold on, you're talking about the DS3121, DS1317(I guess it's a typo), while the picture is from a DS1307
I gave another try to the kernel...
Updated building steps
here.
After a lot of work, I got something:
» Configure, compile and flash the kernel.
» Patch the existing uboot, because the bootcmd only reads 3MB, while there new kernel is larger. The kernel partition is 10MB so there's plenty of room available.
» Boot using the original flash rootfs.
However, there're still lots of issues:
» Screen needs fixing. I have no idea what configuration Hantek is using, but seems to be a simple framebuffer, not using the graphics engine at all, drawing everything by software.
But it looks like the framebuffer is passed from u-boot, so no special config is needed?
» This kernel is 5.4.92, while original is 5.2.0. Hantek uses several custom kernel modules for scpi, keypad, fpga... which will refuse to load because the kernel version doesn't match.
Additionally, I found a more recent kernel,
5.4.140, sadly we're tied to 5.2.0 for the same reasons.
I might try using "modprobe -f" to force loading, will be great if it works instead exploding or something
Luckly for us, the original kernel is still available
here, and there're great instructions
here, so I'll keep working on it.
(Remove [ url] tags, it's a forum error)
git clone [url]https://github.com/Lichee-Pi/linux[/url] -b nano-5.2-flash
cd linux
touch .scmversion # Required to prevent build from appending a "+" sign to the kernel LOCALVERSION, or it'll make "licheepi-nano+"
export ARCH=arm CROSS_COMPILE=arm-linux-gnueabi-
make licheepi_nano_defconfig
make menuconfig
make -j8
» Current status: System dies after "Booting kernel...""
That 5.2.0 kernel has no DMA support, pretty crappy support overall, things that 5.4.92 fixed.
If at least I manage to boot it, I might try porting the patches from 5.4.92...
It's a shame that nobody with linux knowledge joins the business!