Sierra Wireless MC-7455 card for W-520

[wsalomon]

As a last addition to my W-520, I'd like to add the last version of Sierra Wireless's 4G LTE mini-PCIe card, the MC-7455 (subsequent cards are M.2 format).

I am using an un-whitelisted BIOS 1.46 (8buj25us)(Oleh) which works well for an Intel AC-7260 WiFi card (which otherwise gets an 1802-type error).

The first MC-7455 card I tried, when inserted, with the the modded BIOS displayed a Green On-Off switch back-light, then locked on a black BIOS screen. Taking the card out, it booted normally.

Thinking this might be a defective card, I tried a second MC-7455 card, with the same problem.

It appears that the only "real" WWAN card for this is the Gobi-3000 MC-8355 Sierra Wireless Card (60Y3257) which is a 3G version, which is soon to disappear.

Is there something else that might work? Have I hit two successive bad MC-7455s? Does another modded BIOS work, when the Oleh version does not?

Thanks for thoughts in advance.