Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

I dared to unlock my bootloader again by restoring my saved mmcblk0p17. To verify that it works, I tried to boot the unmodified /boot/boot.img image by copying it over to my computer and then issue a fastboot sequence. However, that does not seem to work for me. The phone resets and I see the charging screen only.

However, the boot-telnet-initrd.img provided by djselbeck works fine.

What is going on here? Isn't the original image supposed to work over fastboot?

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

And right after I posted this I found out that it actually did work – I just wasn't aware of it. :-)

When the charging screen comes up, I need to press the power button long enough once to actually boot up the system.

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

Though having an overview of the partition layout on Jolla device will help. So, I compiled parted for Sailfish (it is on my openrepos)

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

scary:
* lots of gibberish
* "drm"
* "security"
* why does this need to get done by a community member (kudos nieldk!)? Basically doing RE. Shouldn't such elementary fundamental stuff - including proper comments on purpose of each partition - be in the "Jolla 101" wikipage published by Jolla even before 1st device shipped? Dang, where's that URL to this wikipage? I seem to have lost it...¡

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

That crap is due to the Qualcomm chipset. The thing is built so that it needs all that hooba to boot up & work. Sad really :(

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

My next try :
Like, I believe Joerg_rw also found, is the 'secret mode' when pressing vol-up on power-on.
I believe this may be an entrance to a quick-recovery.

What I want to try (once I get around to buying a 16G SDcard)
This requires an unlocked bootloader.

insert 16Gb SD card
fastboot -i 0x2931 boot boot-telnet-initrd.img
telnet 192.168.42.17
dd if=/dev/mmcblk0 of=/dev/mmcblk1

power off
power-on - holding vol-up

And see if this will start a flash from SD card, now containing a proper partition layout, like the device.
Possibly, if it work, it is also doable to just create the partition layout on the SD card, and dd mmcblk0p17 to mmcblk1p17

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

What I was thinking the other day was a bit of similar thing that you have in mind;

I suppose it's possible to create a recovery kernel that actually swaps the mmcblk0 and mmcblk1 devices in the device so that if you have a copy of the filesystem on your external SD card you caould run the device fully on that.

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

I took an image of the entire /dev/mmcblk0 from the "fastboot rescue mode". This way I can view the partition layout with parted or gdisk on my computer without risking any damage by accidental modifications.

Not sure if there is anything useful in this, at least some of these have names that may reveal their function. I guess all those "Q*" partitions are something internal from Qualcomm and probably uninteresting. The bootloader chain would be "rpm" -> "sbl1" -> "sbl2" -> "sbl3" -> "aboot" according to some sources on other Qualcomm-based Android phones that turned up on a quick web search (sbl = secondary bootloader).

"persist" is mounted on /persist and appears to contain WLAN driver configuration, including MAC addresses. "drm" is mounted on /drm and it's currently empty despite the standard lost+found directory. No idea about "security" and some of the others, though.

I don't think these partitions are scary, this is just the way it is set up by Qualcomm as vendor. In defense of Jolla, what would be the purpose of documenting this publicly? I would even expect that the documentation provided by Qualcomm is under a NDA…

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

If you want to experiment with a different OS, you could just boot from fastboot with "root=/dev/mmcblk1pX" as kernel argument and run from the SD card.

For a clone of the "sailfish" partition, it would probably be a good idea to change the partition UUID to something different and change /etc/fstab accordingly to avoid mounting home or swap from the internal storage. Probably needs some more changes in /lib/systemd/system/*.mount for things like /firmware or /var/systemlog.

Re: [HOWTO] Comprehensive Firmware Flashing Guide for Jolla
 

That list of partitions aren't necessarily all used (like drm and etc.), but are probably required for Qualcomm SoCs. Pretty weird layout if you ask me. Jolla should document that stuff in some hardware docs section. That would be community friendly. Unless Qualcomm forbids them to do it. No idea.