[mk01]

This alone mean no error. This is because you are installing on to Alpha5 which is ext4. xbian-update expects at this stage of xbian-update postinst script already update to B2 (from B1.1) - if this would happen step by step during the time, there would be BTRFS now.

Expects doesn't mean needs and absolutely doesn't mean require. At this point there could be even NFS root, error checking + failing script is suppressed there.

The second report is the same case.

But then when you restart not a beep? black screen? My tip is wrongly updated cmdline.txt with rootfs and some other parameters which are taken from user values during cmdline.txt template changing. as again expected was somehow BTRFS (any Beta1). And definitely wrongly expected.

I was trying to figure out this one issue since beginning but realized this only one as internally I was always testing including FS conversion to simulate conditions close to user. That means Alpha5 -> B1. reboot (auto convert) -> apt-get install xbian-update. And could fight with anyone that it must be ok.

Your /boot will probably hold correct kernel and initramfs. Even if the cmdline.txt used for boot can be broken, ther should should be either backup from old one or template for new one (cmdline.new or later stored for reference cmdline.default). If I'm right, then you have cmdline.default. What you need is copy it over wrong cmdline.txt and update cmdline.txt to allow B2 install - still on ext4 - boot like beta2 but trigger conversion like <B1.

so keep all as is, even keep rootfstype=btrfs, but change rootflags=subvol. …. just was looking at the code and don't change anything as when ext4 will be found (but with parameter btrfs on kernel command line), convert will start on unmounted system - so doesn't mnatter and after finish the mount option parameters will be not changed there (as this was task for xbian-update) so after reboot would hit error mounting root and dropdown. so just copy .default over to .txt.

I'm mistaken, I just crated quite nice mini-how-to-restore . what nobody will use anymore, because is dealing wiuth A5.

let me know please.