Would the HP-15C Limited Edition Firmware Age Away?

[Dan Grelinger]

In a conversation that I am having with an Asian HP collector, he said he put an HP-15C Limited Edition away with batteries removed for 5 years and recently took it out to test it. After an initial "Pr Error", the calculator would not operate. He called HP and they said they do indeed recommend storing the calculator without batteries, and secondly, that after a long period of time, the firmware would fail and the calculator would not longer be usable and could not be repaired. I don't know if the two statements are related.

I assume that the HP-15C Firmware is in flash memory. From what I know about flash, it does have a limited storage life (10 years, 50 years?), but that this period is not influenced by power being applied or not.

Is there any danger of an accelerated firmware loss if the calculator is stored for an extended period of time without batteries installed?