How do I delete startup-config.legacy from an ICX 6450?

[daniel_rose_aod]

I have some switches I'm disposing of, and the file startup-config.legacy is sitting on the flash with no way to delete it.  The CLI only lets me remove boot images or specifically startup-config, but not this file.  Any clever ideas here? I can't find any way to delete it from boot monitor either, the closest I have is this:

ICX64XX-boot>> sflash erase startup-config.legacy
Usage:
sflash  - read, write or erase the external SPI Flash.

But I'm not even sure that's the correct command, even if I could guess the syntax.