If you've used the following
GUIDE to configure Koreader to automatically set the last opened book's cover as the sleep logo, you could try running this code to create symlinks for the power-off/boot logos:
Code:
sleepLogo=/mnt/ext1/system/resources/Line/taskmgr_lock_background.bmp
offLogo=/mnt/ext1/system/logo/offlogo/koreader_cover.bmp
bootLogo=/mnt/ext1/system/logo/bootlogo/koreader_cover.bmp
ln -sfn $sleepLogo $offLogo
ln -sfn $sleepLogo $bootLogo
(Run this using pbterm; or unzip the attached .app file to /mnt/ext1/applications, reboot and run, it will delete itself after a successful run as it shouldn't be needed again.)
Once the symlinks are created, manually change (device settings menu) your power-off/boot logos to:
koreader_cover
With these logos selected it should link to whatever book cover image has been set as the sleep logo by Koreader, keeping them synchronised.
*As before, a device reboot will be needed after a new book is opened before its cover is active. I don't think there's an easy way of avoiding the reboot as (I think) these logo assets are loaded into the memory stack at startup.