[Arm-netbook] next step is a boot image

Andreas Grapentin andreas at grapentin.org
Mon Jan 16 19:10:08 GMT 2023

> On 16. Jan 2023, at 20:01, Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:
> On Mon, Jan 16, 2023 at 6:56 PM Andreas Grapentin <andreas at grapentin.org> wrote:
>> In the process of attaching peripheries, I must have blown something on the microdesktop, the power LED no longer lights up, tested multiple chargers. I’m fairly certain that the LED did light up green when I started working on the board today. Is it possible that I blew a fuse somewhere?
> yes it should. no there's no fuse.  you'll need a multimeter, be *careful*.
> i suggest taking the Card out.  if it's really borked you can power it
> with a 5V USB "charger" cable (into the 2 standard USB sockets).
> also, check you inserted the Card correctly: not one row along or one
> pin along, and make sure no contact between the two PCBs.

forgot to mention, I’m using the expansion header on the micro desktop for the UART connection. Power to the EOMA card directly through the microUSB works, that’s what I’m doing right now. I haven’t tried the USB sockets on the micro desktop though, that might be worth a shot.

>> I’m confident that this is salvageable, considering that I do get boot loader output through UART. I’ll keep looking into it. If you have any hints, I’d appreciate it.
> it's possible to reconfigure u-boot (etc) to have the OS on the Card's micro-sd.

I believe I’m using a quite old u-boot boot script. Included below. I’m not too familiar with u-boot, any tips what needs to be changed to switch the microSD slot, or maybe include a fallback option to try booting from the internal microSD if the external one is unavailable?

if test -n ${distro_bootpart}; then setenv bootpart ${distro_bootpart}; else setenv bootpart 1; fi
part uuid ${devtype} ${devnum}:${bootpart} uuid

setenv bootargs console=${console} root=PARTUUID=${uuid} rw rootwait

if load ${devtype} ${devnum}:${bootpart} ${kernel_addr_r} /boot/zImage; then
  if load ${devtype} ${devnum}:${bootpart} ${fdt_addr_r} /boot/dtbs/${fdtfile}; then
    if load ${devtype} ${devnum}:${bootpart} ${ramdisk_addr_r} /boot/initramfs-linux.img; then
      bootz ${kernel_addr_r} ${ramdisk_addr_r}:${filesize} ${fdt_addr_r};
      bootz ${kernel_addr_r} - ${fdt_addr_r};

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