...or you could use the good, old index method... store an index of alphabets and the first location in flash where it occurs. You could do this in a very small piece of code while you actually download the data and store it to flash. As you mentioned, you can do the sorting outside the uC and transmit the sorted list itself, so that you don't need to worry about the sorting or the integrity of your index.

For retrieval you jump to the first occurence of the alphabet in your flash memory, and then search sequentially for the string you want. Depending on the sort of data and the availability of memory (RAM and flash), you can optimize the design of your index and the search algorithm.

I guess this method will be much easier to implement on a uC than hashing...

kundi