40-150 f2.8 bricked by EM1mkii

karlreed wrote:

Airmel wrote:

karlreed wrote:

My experience of USB connections via hubs is that they can be AWFULLY flaky. So, this needs to be kept in mind if updates must be by a direct connection to the computer, ior, internet rather than via a card.

However, best practice for this kind of update is NOT to destroy the current version until the update is complete AND the system has been re booted.

Unfortunately, most embedded systems don't have anywhere near the resources (think firmware storage space) needed to permit this duplication.

In these systems, there is usually a small portion of code designated to perform the update/re-flashing (and which is not updated in the field). That small, "update" portion of the code takes control while the main firmware package is overwritten by the new version.

The process is a lot like performing brain surgery on yourself. As with all complex things, the devil is in the details.

This can be done by booting via a pointer to the active system. The VERY LAST THING the updating s/w does is to change this pointer to point to the new systems.

Don't apply general purpose computer "PC" thinking to embedded systems, They are completely different.

I am familiar with the use of "boot" software, and, also, "boot strapping" as a means of starting systems., (and doing a few other things as well. However, Oly could quite easily have the camera copy the new system to a SD card on the camera, and, the copy that into the camera.

Copying to the SD Card first? How do you know they don't, and for that matter, what in the world would it change if they did?

Your post above suggested the device ought to have an extra 100% program storage space simply so that two copies of the firmware can be loaded at a time. Keep in mind that in embedded systems of this sort, the SD card is used for bulk storage only.

An entirely different memory area (unavailable to the user) is used to boot the OS, so your suggestion would increase the camera's internal program storage by 100%.

*************************************

Product Manager: Hey Joe, how much space does your beta firmware take?

Joe Developer: Oh, about 175MB give or take.

Product Manager: Okay Joe, that's great. How much total code space will be needed for future firmware expansion?

Joe Developer: Well, I think we can live with 256MB total. In other words 175MB is used today and we will have another 80+MB of additional room for expansion with firmware updates, new features, etc.

Fred Designer: Hey guys, I have a great idea, lets double the size of the program storage area to 512MB so that we can keep a second copy of the firmware in memory only to be used during update. The additional 256MB will only raise the cost of the Bill of Materials by $20 and just think how cool it will be?

Product Manager: Get lost Fred. You're fired.