Under what OS are you updating (bear in mind the BIOS update may not work under Windows 10, which this system was never designed to support)?

If you're running Windows 10 you will need to prepare a bootable flash drive with an earlier version of Windows to do the update.

yes running win10

my issue started a week ago with persistent BSOD when I pull the power cable from the laptop.  In trying to find a solution to that (iastor?.sys is reported as the issue), I got onto the dell site and realised I don't have up to date bios.

So... should I continue down the path of updating bios, or should I just focus on the BSOD as being an unrelated issue.  Feel the whole thing caused by a windows update but can't be sure.

If I should continue with the bios update, can you provide some pointers as to getting a bootable usb sorted out?

Otherwise should I just reload the old (2013) dell drivers for intel rapid stor?

Thanks

I just looked at your original post.  Your error arose from trying to flash the BIOS of an XPS L511z on an XPS L521x system board.  The correct latest BIOS for the L521x is A18

https://www.dell.com/support/home/en-us/product-support/product/xps-15-l521x/drivers

I doubt this is a BIOS issue, though. 

Does the system have a single hard drive, or a cached hard drive (a conventional drive + a small 32G mSATA SSD)?

This is a snippet of what comes up with a search on my service tag:

thanks Ejn63,

It does look strange, as when I type in service code it reports both the A18 and BIOS (which I installed) and the A09.  So happy follow up with the relevance of the A09 version for another time.

Rightly or stupidly I tried to roll back the driver (firstly by trying to reinstall the Dell Rapid Store Tech driver, then by using windows roll back option on the device), and now computer not booting at all - goes into and endless loop of trying to start, attempting to go into a recovery, trying to start (it could be there is no winRE partition as causing this).  I am increasingly resigned to having to reload windows via a boot usb.

The HDDs are a 1TB (WD conventional) and a 128GB mSATA from memory.

Let me know if there is another credible work around to having to reload OS.

Thanks

I got a repair sorted out courtesy of a win10 boot usb.  That seems to have fixed the issues (both boot and the BSOD).

Still not certain why dell reports the A09 bios as relevant to the pc.  I see when I click on the compatible systems it reports:

Compatible Systems
XPS 15 L521X
XPS 15Z L511Z