Dear all,
not really important, but still two remarks:
* GPRS related questions should preferrably go to the osmocom-net-gprs list
* RACH for packet service is not equal PRACH. PRACH is a dedicated logical channel on the Um interface that _can_ be enabled (like PBCCH, PCCCH, ...) but whihc is neither supported by osmo-bts/osmo-pcu, nor used anywhere. The 3GPP removed the PBCCH/PCCCH and all related channels several years ago from the specs, as there was no operator known to use any of them. So new handsets no longer (have to) support those channels, which means it is utterly useless for a new implementation like the Osmocom one to bother to support them.
Regards, Harald