git clone https://git.buildroot.net/buildroot buildroot
git clone -b arc64 https://github.com/foss-for-synopsys-dwc-arc-processors/buildroot buildroot-synopsys

Write sdcard.img to micro-SD card using dd:

sudo dd if=sdcard.img of=/dev/mmcblk0 bs=1M

Set these options to build vmlinux instead of uImage:

# BR2_LINUX_KERNEL_UIMAGE=n
# BR2_ROOTFS_POST_IMAGE_SCRIPT=""
BR2_LINUX_KERNEL_VMLINUX=y

overlay/etc/network/interfaces makes HSDK to use a static address 192.168.1.142 (set BR2_SYSTEM_DHCP="eth0" to enable DHCP). Here is content of ~/.ssh/config for connecting to it through SSH:

Host hsdk
    HostName            192.168.1.142
    Port                22
    User                root
    IdentityFile        ~/.ssh/keys/arc

Copy client side keys:

cp keys/* ~/.ssh/keys/

Overlay already contains pregenerated client side keys. You can generate your own keys:

$ mkdir -p ~/.ssh/keys
$ ssh-keygen -t rsa -C "arc@arc"
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user/.ssh/id_rsa): /home/user/.ssh/keys/arc
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/user/.ssh/keys/arc
Your public key has been saved in /home/user/.ssh/keys/arc.pub

Add your public key to the overlay directory for all users:

mkdir -p overlay/hsdk/.ssh
cp -f ~/.ssh/keys/arc.pub common/overlay/root/.ssh/authorized_keys
cp -f ~/.ssh/keys/arc.pub common/overlay/home/user/.ssh/authorized_keys

Overlay already contains pregenerated host keys. However, you can generate your own keys:

ssh-keygen -A -f overlay

Now you can connect to the board this way:

1. Serial: minicom -8 -b 115200 -D /dev/ttyUSB0 -s (disable hardware flow control)
2. SSH: ssh arc-hsdk-root

mount -t debugfs debugfs /sys/kernel/debug
sysctl net.core.bpf_jit_enable=1