Does it mean the SAMSUNG F9F series is supported only in 64Mx8 bit size?
Blindly guessing, that other sizes may be possible as well. Only 8 bits are wired. But I may be wrong and only selected memory types are recognized.
But there are two Flash slots. One is empty. So you may be able to solder twice more NAND flash.
I think it would be possible to modify mainte.bin to accept other flash IDs.
It will not help. First stage boot runs from PROM (at least on SL-Cxx00 models). It loads second stage boot from NAND. If NAND flash chip is not recognized, second stage boot never happens.
You would need to replace PROM by NOR flash to be able to change flash IDs. (And you would need to know the checksum algorithm to keep it running.)
Only modern OneNAND chips (that did not exist in time of Zaurus release yet) support cold booting.
On "C+D" menu and "CF update" in "D+M" menu, both LEDs are on for a second or two then they start blinking. What does this exactly mean?
(I'm checking the code in mainte.bin and diag.bin to find it out. flash code starts at 0xbc554, mainte loaded at 0x0, diag.bin loaded at 0x7c000)
BTW the 'NAND Bad Count' gives me 8192 blocks with a nice
ERROR! No partition info
code=(610)
message. I think it's dead.
Well, I don't know, what LEDs mean.
You can run diagnostics from the PROM. In the default setup, it is exactly the same as the NAND diagnostics (again on SL-Cxx00 models, I don't know SL-Cxx0 models), but it is capable to run even in case of totally broken NAND. I don't remember the key combination exactly, but I am guessing something line Fn+D+M. (You can find it somewhere in forum.)
Partition info is part of one of the first blocks of the NAND. It exists there in many copies for the case of broken blocks. If all reserved blocks are broken, Zaurus is not capable to find the partition table.
You can run ROM diag, try to reflash fresh NAND image, and see whether it will work.