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My web"nozing" told me that the two (the Rpi1B 256 and 512) variants are virtually the same hardware spec-wise (with the exception of the amount of RAM ofc. and maybe the SMT/cirquit layout).

  • Could I simply take out the SD card (running Raspbian wheezy) from the 256MB one and place it into the 512MB one (any snags to be expected)?
  • What about the other way around (start with 512, cutting back to 256)?

I would expect the OS to be "smart" enough to "adapt" to the extra (or less) amount of RAM. But does it?

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I would expect the OS to be "smart" enough to "adapt" to the extra (or less) amount of RAM. But does it?

Yes. There are only two basic forms of pre-compiled kernel, one for the single core ARMv6 models and one for the quad core ARMv7/8 models.

Could I simply take out the SD card (running Raspbian wheezy) from the 256MB one and place it into the 512MB one (any snags to be expected)?

Sure. In fact, presuming it's been updated to include recent kernels, you could put it in any model of pi -- except it probably won't fit most of them, unless you happen to use a microSD card with an adapter.

However, that doesn't mean there can't be any snags. Most of those would apply to the quad core models though, and in particular the Pi 3.

The only thing that would impact the 256 vs. 512 MB models would be if you had a software stack configured to run at boot that required more memory than the former could provide -- which is easy enough to check.

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    One potential snag would be the SSH. You may get a dire warning about a potential man in the middle attack if you do not regenerate the keys and or change the hostname. – Steve Robillard Aug 25 '16 at 22:57
  • @SteveRobillard If you are confining this to a LAN it is probably fine to use -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null to avoid the warning -- then cross your fingers someone didn't attach their own pi under the front porch O_O – goldilocks Aug 25 '16 at 23:36
  • I am far to paranoid to just do that. I would regenerate the keys it takes < 5 minutes. You never know when some crazed Canadian with a Pi is hiding under your porch. How to regenerate the SSH keys cyberciti.biz/faq/howto-regenerate-openssh-host-keys – Steve Robillard Aug 25 '16 at 23:42
  • In comp sec boot camp they do surprise 3am drills where you have to replace all your keys blindfolded in the freezing rain and if you can't login within 180 seconds then you get to stay awake for 24 hours and try again ;) – goldilocks Aug 25 '16 at 23:50
  • @goldilocks thanks.. again.. you rock (I hope to be able to help others similarly in the future)! The only thing that would impact the 256 vs. 512 MB models would be if you had a software stack configured to run at boot that required more memory than the former could provide -- which is easy enough to check. So only a possible issue when "dowgrading"? And how to check that? – woosting Aug 25 '16 at 23:54

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