Hi,
1. It looks like, on occasion, a power cycle will cause FLASH to develop a 
bad erase block. After 549 power cycles I got 12 extra bad blocks in addition 
to the 2 original (manufacturer marked) bad blocks. I do not believe these
blocks are actually bad because I have not erases FLASH nowhere near the maximum
count.

2. Finally I got a message:
nand_read_ecc: Failed ECC read, page 0x0002710e
and after a power cycle verification application failed to verify data: 
read=0xec expected=0xe4
Looks like one bit did not program from 1 to 0, but why didn't ecc catch it?
I'll take a look at the rest of the file tomorrow..

Sergei Sharonov