Suppose you have a Flash chip (NOR flash) which you are using for example for data logging, performing sequential writes regularly on it.
The question is what if the power goes off during a page write: Is it possible to "fix" the page by rewriting the same contents over it?
By my knowledge of Flash devices this should be possible as writes turn cells from 1 to 0, so an incomplete write I think should only drive cells more or less towards zero (so retrying the same pattern again later should only reinforce it).
The exact design is a data logging device which has a large NOR flash array for data storage and FRAM for intermediate storage (small, but supports immediate writes, so data isn't in danger of being lost during periods when the Flash can not accept it).
I can not do a complete erase + rewrite cycle when detecting such a condition (interrupted write) since I have no room to store a complete erase sector which is significantly larger than a write page (64Kbytes versus 256 bytes), so the most straightforward thing to do would be attempting a write again if the previous power off left behind an unfinished page write.
(Detecting the unfinished write is done by polling the chip's status, and maintaining a related state machine in the FRAM, so not by comparing data which might falsely indicate a succesful, but "weak" write due to a later power off during the page write)