Pinning glibc to squeeze is, probably, going to require downgrading few other things to squeeze, to. This or other way, doing so is replicating lenny/squeeze mix we had earlier, with all multitude of problems for future.

Personally, with such perspective, I would rather opt for downgrading to Squeeze entirely, so I'm not (again, personally) interested in spending my time for pinning/mixing efforts. Of course, everyone is free to try and I'll gladly discuss results.
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@fw190, that command was "nice" and was to be applied in line where you copy (cp) files - but, if your device would be to reboot, nice won't help, anyway, so as pichlo said, try without it, first.

Generally, if you have swap on microSD, and you'll be copying files *to* eMMC, you shouldn't get reboot problems.

/Estel