Why can't I boot SP3 from USB drive?

[wps81]

Can't boot SP3 from USB drive

I installed windows 10 preview and now want to reinstall windows 8.1. I have got USB bootable drive with win 8.1 ISO content written to it. The drive can boot my desktop PC but can't boot my SP3. SP3 reports BCD error when try to boot from USB. Anyone know this ? Thanks.

 

[stephen_az]

Re: Can't boot SP3 from USB drive

There are some instructions that seem to work on the last page of this discussion: Surface Pro 3 will not boot from USB - Page 5. The most obvious is whether you also have an SD card installed in the machine - seems to make a difference for some. It did on one of my machines. Otherwise one of the other tips may help....