In fact, most x86 chips to this day work like this - they just start executing code at FFFFFFF0 with the expectation that the chipset has mapped the BIOS flash chip there. A lot has been said about the GPU doing MOST of the boot sequence but I have my reservations. No Trustzone settings are enabled in the boot sequence.Here, you can say that BIOS is the bootloader (though it also provides services to the OS, similar to bootrom). That allows a bare-metal coder (embedded systems) to use the vast majority of the CPU Flash ROM as vector tables so you can poll the Hardware and set up vectors as required.Once those are loaded into the phone, you don't need the upgrader files any more unless you need to upgrade other phones.If you have old phones (who are not capable of the new bootrom), they will make an attempt at the upgrade and then ignore it, so you can save your phones some hassle by removing the bootrom-upgrader when you are finished.
On the very simplest chips there may be no boot ROM or boot loader at all - they just try to fetch and execute instructions from a fixed startup address. So, in the face of the official version of the boot sequence, I see from the original GPU data, 32K is copied into L2 cache (since DRAM hasn't been switched on) and from that point, the CPU runs code to load the BIOS from the SDRAM.
- In the ftp directory (everything is at root), I have also placed the 4.4.0 Boot Rom files, which look like this: 2345-12360-001.2345-12365-001.2345-12375-001.2345-12450-001.2345-12500-001.2345-12560-001.2345-12600-001.2345-12670-001.It seems to me that the IP5000 should, using its 3.2.6 configuration, see the bootrom upgrade files in the polycom directory and just load them. I put the 4.3.0 Bootrom in the ftp directory (it would not work with the 4.4.0 Bootrom). Apparently, I was not able to go directly from 3.2.6 to 4.0.1. So I judge that it is a matter of the right order of upgrading. You put the new "upgrader" files in the polycom ftp directory. The upgrade consists in the phone updating its own "brain-reading" files that are kept inside itself.
After that, I think I ought to be able to reboot the phone with the 4.0.1 configuration. It does say that in the manuals, but there are so many different versions of everything out there, and so many pdfs to read it is hard to decipher. These will allow the phone to read the files that you get from polycom, which are the "brain" of the phone.
Also, I would like to know a name of a popular bootrom that is typically used in ARM systems. Bootrom (or Boot ROM) is a small piece of mask ROM or write-protected flash embedded inside the processor chip.
It contains the very first code which is executed by the processor on power-on or reset.
Search for updating bootrom:
The TZ stuff has no useful properties since The Smurf Suite proves that it isn't secure.