It shows "cannot read 'sideload' " message during installing

[Ethan Chang]

Milestone: M8
Device: Nexus4

Summary: Perform dualboot.sh to install dualboot on N4, and it shows "cannot read 'sideload'" during installing

1. Run ./dualboot.sh
2. It will reboot N4 and starting flash

Expected Result:
It will complete the installation and reboot to android

Actual Result:
It shows "cannot read 'sideload'" and stop to continue.
You will need to press "go back" and then it will retry to complete the sideload

Note:
Dev:04dbf50e910b4fe7: Waiting for adb recovery to be ready
Dev:04dbf50e910b4fe7: Creating update command
Dev:04dbf50e910b4fe7: Booting back to bootloader
Dev:04dbf50e910b4fe7: Waiting for fastboot to be ready
downloading 'boot.img'...
OKAY [ 0.267s]
booting...
OKAY [ 0.002s]
finished. total time: 0.269s
Dev:04dbf50e910b4fe7: Waiting for adb sideload to be ready
* cannot read 'sideload' *
Dev:04dbf50e910b4fe7: Waiting for adb recovery to be ready

[Ondrej Kubik (ondrak)]

I tried this one and I can't reproduce it.
Can you reproduce this one every time?

[Ethan Chang (ethan.chang)]

@Ondrej
I can reproduce it on both N4 and N10 and I found that SuperSU doesn't installed, so when it try to install ubunt it will always fail

Note:
If use CM image then it won't happen this issue.

[Ondrej Kubik (ondrak)]

Can you put here more details please?
Is this N4 and N10 with factory image? ( mind you need to fastboot flash system system.img to make sure there is no remain of previous installation)
I have run $ ./dualboot.sh factory restored N4 and all went fine. Installed both SU and Ubuntu installer.

[Stuart Langridge (sil)]

I am upgrading -- I already have the previous Ubuntu dual boot system installed, and am experiencing this bug.

OK, I think the problem is that the app update is not actually being downloaded. Follow the bouncing ball:

If we specify "dualboot.sh update" (with explicit "update" parameter), we do this (lines 361-4):

    elif [[ "$ACTION" == update ]]; then
    echo "Dev:$DEVICE_ID: selected update install"
    download_app_update
    install_ubuntu_installer $UBUNTU_INSTALLER_PACKAGE

but if we do not specify a parameter, then we go into auto_mode (lines 372-3):

    echo "Dafaulting to auto action"
    auto_mode

and auto_mode then detects that an update is needed (lines 213-4):

        echo "selecting UPDATE mode"
        install_ubuntu_installer $UBUNTU_INSTALLER_PACKAGE

but note that it does not run download_app_update!

Explicitly running "dualboot.sh update" does download the app update, and makes the sideload error not occur, and the script completes without error.