I have decided to go for a little Intel-N5095-powered Mini PC, sweet 8.5x8.5cm and close to the size of a Raspberry. The device is having two Ethernet ports, which makes it ideal for OpenWRT.
I have created the USB Stick with ext4-combined-efi, that worked so far. But currently, the system boots from USB Stick, as soon as I detach the, stick, the system won't boot. I need to permamently install OpenWRT on /dev/sda. I have tried this by the command "DD if=...img of=/dev/sda". This did not work out.
Any hint for me?
SOLUTION:
The command to copy the image to the internal drive has to use the image for efi, otherwise the system will not boot.
cd /tmp
wget https://downloads.openwrt.org/releases/22.03.3/targets/x86/64/openwrt-22.03.3-x86-64-generic-ext4-combined-efi.img.gz
unzip openwrt-22.03.3-x86-64-generic-ext4-combined-efi.img.gz
dd if=openwrt-22.03.3-x86-64-generic-ext4-combined-efi.img of=/dev/sda
Yes, you are right, the command starts with "dd" this is what I have executed. Before executing, the was a "naked" Win11 installed, after executing, I get this result on the console:
root@OpenWrt:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 238.5G 0 disk
├─sda1 8:1 0 16M 0 part
└─sda2 8:2 0 104M 0 part
sdb 8:16 1 3.7G 0 disk
├─sdb1 8:17 1 16M 0 part /boot
│ /boot
├─sdb2 8:18 1 104M 0 part /
└─sdb3 8:19 1 239K 0 part
Clearly, dev/sda is the internal SSD, dev/sdb the USB Stick. I see the smaller 16mb partition on both entries.
It depends on the BIOS and its settings, these days I'd always try the combined-efi image first (and try really hard to get that one working, before regressing to the non-efi images).
If he's writing the image, it shouldn't be a problem, but you can always replace the root= param value with root=/dev/sda2 in Grub, but I'd try the efi 1st.
@Matthias17 how far are you getting in the boot sequence.
So, I have redone the command, explicit with the file "openwrt-22.03.3-x86-64-generic-ext4-combined-efi.img", for simplicity I renamed it after unzipping to "openwrt_efi.img":
dd if=openwrt_efi.img bs=1M of=/dev/sda
After powering down the system, ejecting the USB Stick, no bootable device is available on next start.
Thanks for your support. A little impression from this tiny device: It's powered up by 12V / 2.5A PoE Splitter with DC jack. Dual-NIC by Realtek with 1Gbps, M2.2240 SSD with 256GB, which can even be extended. Unfortunately the RAM size is fix and cannot be upgraded.
By USB the VDSL modem is powered up as well, which "only" consumes 0.5A.