Thread: PRS-650 Additional Memory?
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Old 03-07-2011, 07:25 PM   #23
delphin
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Posts: 434
Karma: 346901
Join Date: Dec 2010
Device: SONY PRS-650
Quote:
Originally Posted by elcreative View Post
Delphin, you also didn't mention how many books you tend to carry with you on your reader...
Along with a few dozen mainstream titles, I have about 1500 public domain titles from feedbooks, which includes a mix of full length books, novellas, and short stories.

When I first transfered all those books onto an SD card, and inserted it into my PRS-650, there was a 2 or 3 minute delay while everything was indexed, but this seems to have been a one time delay, because now I can remove or reinsert the card with only a few second change in the startup delay.

Extrapolating to several thousand books, I can see why you would find the 'no scan' feature of the PRS+ firmware very handy.

I wouldn't trivialize the danger of 'bricking' your reader because I have already read reports from at least two individuals who killed their 650 while trying to install custom firmware, and when this does happen, there doesn't seem to be a damn thing you can do except send your reader off to Sony and hope they will still honor the warranty.

The good news is that this danger seems to be mostly associated with flashing the reader for the first time, because that is when the main internal embedded Linux root file system is modified and re-written.

AFTER you get past this first slightly dangerous point, your comments about how PRS+ works are essentially correct and it would be fairly difficult to do any permanent harm (because if PRS+ locks up, you can always stop the loading of PRS+ by hooking up the USB, then remove the offending code).

Looking at that first time flasher code, it looks like it loads a copy of the new firmware image onto the reader's flash drive data area then checks it via an MD5 checksum to make absolutely sure that nothing is corrupted, then reboots and copies that new image internally to the Linux root partition on the reader.

Doing it this way, in theory, even this first more dangerous flashing operation SHOULD be a fairly bullet proof procedure as long as you don't loose battery power, or intentionally force a power down while the copy is in progress.

So I must admit that I am mystified at how a few folks managed to brick their readers anyway, but THEY DID, so I think that a little caution is in order.

Last edited by delphin; 03-08-2011 at 01:15 AM.
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