Looking for WRITTABLE RESQUE linux distro for USB drive under 8GB installed

Looking for **WRITTABLE** resque/recovery type LINUX distro for USB flash drive under 8GB installed. Current primary usage scenario: write and troubleshoot initramfs script for non-standard boot process (details doesn't really matter here). By "resque type" I mean without heavy stuff like office/video/multimedia, not necessary loaded with all kinds of recovery tools. Should support/have: - minor **soft installation** and fstab, other /etc files modification (i.e. ROOTFS need to be WRITTABLE, or /etc at least) - mount of LUKS + BTRFS partitions & subvolumes - able to run Bash scripts - have (or be able to install) plain text editor (will be used for shell scripts editing) - Terminal - Chroot (or be able to install) I tried Systemresque 10.02, which has touchpad DISABLED (there's a ticket on gitlab for 3 years about this). One cannot even install any of recent versions 11.x with their own USBWriter, and has other issues noticable almost immediately. Otherwise Systemresque would fit the target. Haven't given up on Systemresque completely yet though. Most of the time I spend in dual panel file manager or in terminal, therefore GUI isn't important. Interface similar to Cinnamon or Windows 7 would be best if there's a choice, but again not important. This is a laptop with 1 disk, therefore installing full size distro to another disk is not an option. Thank you.