Engage: Unable to onboard switch since 13.0.6.7 recall

Engage (2.5.1.9) still prompts an undefeatable firmware update to the latest available online when onboarding new switch. This is still 13.0.6.7, despite its apparent removal due to installation issues. This update appears to fail after reboot, the switch never shows online.

I am able to access the switch via browser, and can manually install 15.0.3.26, but am nonetheless unable to onboard it into Engage.