Well, taking the effort and porting back fixes to a kernel version quite old makes only sense when it is clear, when a new kernel version for CoreELEC comes into play as higher versions already exist that solve this issue here.
Otherwise, it’s worth to switch from CoreELEC to LibreELEC. That’s an approach consuming less work effort and allows getting a more up-to-date kernel version with less problems in this regard.
Well, I wanna give a back port from a 4.9.168+ kernel version a chance and I’m absolutely open for that. But again - this makes only sense, when CoreELEC does not have the plan to switch to this version or beyond in the next releases.
Is there anybody here who knows about that plan?
IMPORTANT: an alternative for those who can switch the file system on the attached external hard drives is using EXT4 instead of BTRFS. Then this kernel related problem does not occur!
@rho-bot: I doubt it’s the boot loader in this case as with an EXT4-formatted external hard drive the issue does explicitly not occur. That’s been practically verified right now. It’s completely BTRFS-related. Beyond, we’re not talking about a file transfer here - just about unmounting a BTRFS file system.
@rho-bot: It’s even worse. When writing the referenced bootloader image to the LePotato CoreELEC 19.3 block device “/dev/mmcblk1” it does not boot anymore and results in a black screen: