Booting with default debian image

[mfritsche]

Is there a guide/ explanation of the boot sequence for dummies?

I can see "Image" and "Image.bak" in /boot/. I want to build a custom kernel based on mrfixit2001's code (with changed configuration), but I haven't found out yet to recover as painless as possible when things go south.

Is there a boot menu in u-boot or something?

[evilbunny]

Is there a guide/ explanation of the boot sequence for dummies?

I can see "Image" and "Image.bak" in /boot/. I want to build a custom kernel based on mrfixit2001's code (with changed configuration), but I haven't found out yet to recover as painless as possible when things go south.

Is there a boot menu in u-boot or something?

The answer is slightly complicated because you have the system on chip with one setting and the uboot on emmc has another.

In the SoC, the order is emmc, sdcard

However the code on the emmc will switch to sdcard if it is bootable.

[mfritsche]

In the SoC, the order is emmc, sdcard

However the code on the emmc will switch to sdcard if it is bootable.

Okay, that means the smart thing to do is try booting a sd card first?

[tophneal]

In the SoC, the order is emmc, sdcard

However the code on the emmc will switch to sdcard if it is bootable.

Okay, that means the smart thing to do is try booting a sd card first?

Yes. Installing any other OS to eMMC, currently, will require either removing or activating the internal eMMC switch to boot from an SD.

[zaius]

Yes. Installing any other OS to eMMC, currently, will require either removing or activating the internal eMMC switch to boot from an SD.

There is a fix for that for the Ubuntu images here:

https://forum.pine64.org/showthread.php?...3#pid50903

[tophneal]

Yes. Installing any other OS to eMMC, currently, will require either removing or activating the internal eMMC switch to boot from an SD.

There is a fix for that for the Ubuntu images here:

https://forum.pine64.org/showthread.php?...3#pid50903

Thanks for pointing that out! I saw some posts alluding to a change in ayufan's uboot, but most were a few years old. I know what I'm installing once my USB adapter arrives!

EDIT: Anyone know if the uboot fix script only works on Debian/Ubuntu builds? I'm curious if I'd be able to use this script with Crouton on ChromiumOS.

[mfritsche]

Next stupid question:

I see that extlinux.conf defines a boot menu. Is the menu only available via serial console?

[danielt]

Next stupid question:

I see that extlinux.conf defines a boot menu. Is the menu only available via serial console?

Yes.

Hopefully this can change as the platform matures (u-boot can draw to framebuffers and listen to USB keyboards but it requires drivers and these don't exist just yet) but at present you need a serial port to interact with the boot menu.

A simple approach is to put your boot partition on an SD card since if you need to change kernel you can eject the card, boot from a eMMC and edit extlinux.conf .

[electriccrowbar]

Next stupid question:

I see that extlinux.conf defines a boot menu. Is the menu only available via serial console?

Yes.

Hopefully this can change as the platform matures (u-boot can draw to framebuffers and listen to USB keyboards but it requires drivers and these don't exist just yet) but at present you need a serial port to interact with the boot menu.

A simple approach is to put your boot partition on an SD card since if you need to change kernel you can eject the card, boot from a eMMC and edit extlinux.conf .

Is this menu enabled by default in the debian image?

I'm in an unfortunate place where my emmc is stuck in a boot loop and preventing a boot from the sdcard. 

I can boot from the sd if i switch off the emmc, but then i can't write a fix back to it...

[tophneal]

If you have a USB c cable you can use rkflashtool to flash to your emmc. Refer to the wiki for the internal button that puts the PBP in mask tomorrow mode.