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View Full Version : Boot block upgrade failures - Explanation


Blacky
April 14th, 2008, 01:13 PM
FIRST AND MOST IMPORTANT.
DO NOT UPGRADE YOUR FLASHSCAN UNIT TO BOOT BLOCK VERSION V2.05.06

It appears that in my eagerness to speed up the USB coms, I reduced one of the USB wait states by 25 nanoseconds too much :((That's 1 cpu cycle at 40MHz.

All test devices here passed with the faster setting, but obviously *some* units are not passing with that setting. I tested the boot block upgrade on a live production unit here just to emulate exactly what was happening in the field. That unit failed as described by a number of users.

By adding the 25ns wait state back into the USB write phase, the failing device now works ok. 50ns will be added to provide a reasonable margin for hardware tolerances.

It does mean a new boot block will be required for ALL FlashScan devices - it will be called V2.05.07.

It also means anyone with a FlashScan device that stops working after a boot block upgrade MUST return their unit to EFILive to have the new boot block installed as there is no way to fix it in the field.

Regards
Paul
swingtan
April 14th, 2008, 01:32 PM
Hi Paul,

For those of us that have working V2 units on BB 2.05.06, is it possible that these may fail? I guess once the new BB is out, that we can flash them OK, though again, there may be an issue if the current wait state is already set too low.


Simon
Blacky
April 14th, 2008, 01:50 PM
Hi Paul,
For those of us that have working V2 units on BB 2.05.06, is it possible that these may fail? I guess once the new BB is out, that we can flash them OK, though again, there may be an issue if the current wait state is already set too low.
Simon

If it is working now then you're ok, it should not fail arbitrarily.

The most likely explanation is that the units that failed were from a different production batch with USB chips that had slightly different tolerances (i.e. less than 25ns difference).
The boot block code pushed that tolerance too far (probably over the manufacturer's specification) but it was not detected during testing here at EFILive because all our test units came from the same production run.

Looks like our future testing strategy will be to add a new test unit to the mix from each production run. - Hindsight is a wonderful thing :doh2:

Regards
Paul
Kevin Doe
April 14th, 2008, 11:22 PM
Hi Paul,

For those of us that have working V2 units on BB 2.05.06, is it possible that these may fail? I guess once the new BB is out, that we can flash them OK, though again, there may be an issue if the current wait state is already set too low.


Simon

I'll second what he said. However I'd like to pose another question. My unit currently works, but is there any possibility that a process will take too long and fail my unit? If there is any chance, can I upgrade the bootblock alone to avoid any chance of a failed FlashScan unit.
Blacky
April 15th, 2008, 08:38 AM
I'll second what he said. However I'd like to pose another question. My unit currently works, but is there any possibility that a process will take too long and fail my unit? If there is any chance, can I upgrade the bootblock alone to avoid any chance of a failed FlashScan unit.

Yes, I highly recommend upgrading to boot block V2.05.07.
Regards
Paul