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Potential problems when upgrading from V1 or V2 boot-loaders to V3 boot-loaders


This information is relevant to firmware upgrades for DM24 Mk3 digitisers.


The Version 3 boot-loader was introduced when the increasing size of the main system code required a memory reorganisation. Version 3 boot-loaders expect to find the main system code in an area of the FLASH RAM which is different to the area used by earlier boot-loaders.


When a system is updated from a version 1 or 2 boot-loader to a version 3 boot-loader, the system code must be reloaded immediately in order to place it in the new location. If this is not done and the digitiser is allowed to start, program execution will transfer to a region of memory containing random data. The usual consequence is that the processor continually reports exceptions in an endless loop and no keyboard interaction is possible.


This problem can be avoided by loading the system code (and, preferably, the DSP code) immediately after the digitiser has rebooted with the new boot-loader. You have a five-second window in which to either initiate this operation (by keying s or to press spacebar in order to increase the time-out to thirty seconds. Provided you take the correct menu option within the timeout, installation can proceed without problems.


If you miss this timeout and allow the system to attempt to boot, you will lose control of the session and the digitiser's processor will continually report exceptions. This situation can be cleared by a power-cycle. It is, of course, important to interrupt the boot process by selecting the system code upgrade option from the menu in order to prevent the problem from repeating.

One-line summary

If you are upgrading to a V3 boot-loader from an earlier version, you must upgrade the system code immediately after the automatic system reboot.