Will desoldering eMMC break the BIOS?

Was looking to desoldering the eMMC onboard storage which just looks like a chip that says the size of the storage on it. I just use external SSD drives and USB’s with operating systems on them with my chromebook to boot into. I have no use for onboard storage cause of its size limitations.

Would the BIOS fail to boot if I desolder the eMMC from the board (without soldering on a new chip)?

While I can’t say for sure, because I’ve never tested it on an emmc model, I doubt it would result in any bricking. On Chromebooks with removable storage you can remove the storage and boot the UEFI settings like normally, and can boot usb/etc. I assume the same for emmc models

Yes de-soldered it and it still works.

However I cant get it (daisy-snow) to boot from debian live, it states I need to chromeOS. Is it possible to install ChromeOS on an SD card or flash drive?

It is not, you must dual-boot or flash MrChromebox’s full rom firmware