If you're looking for such an image, your best bet is to search within specialized Android development forums (like XDA Developers) or GitHub repositories dedicated to custom ROMs and GSIs.
: You cannot flash custom images without an unlocked bootloader 1.5.5 .
This denotes the partition scheme. Early Android devices featuring Project Treble used a single system partition slot ("A"). This contrasts with newer A/B dual-partition systems designed for seamless background over-the-air (OTA) updates.
xz -t system-arm32-a-only.img.xz