I updated to BIOS 1.1.28, from 1.1.27, via the F12 flash update option on 1-18-23, so a bit over one month ago. PC is running smoothly with no problems or BSODs. BIOS Time (in Task Manager) is routinely ~12 sec. Windows Reliability Monitor has been showing a "10" before and after this update.  As always, YRMV!  
I am currently running 1.1.26 and skipped 1.1.27 because of all the trouble with it. I am going ahead and install 1.1.28 using the usual USB FAT32 method that i have used for the last 2-3 BIOS updtes. Has anybody had trouble with this 1.1.28 using this method? I will go back into BIOS after the update and change all the usual items to stop Windows Capsule Updates.  BTW, I am not having any trouble, just figured enough time had passed to update to 1.1.28 safely.  I have been holding back windows updates for 2-3 weeks until I install 1.1.28.  Thanks.
XPS 8930, update BIOS to 1.1.28