GPRS decode tutorial

Hello everybody Not sure if someone has pointed it out already, but I'm getting stuck following the gprs decode tutorial

[...]

- Prepare OsmocomBB's burst_ind branch

cd ~/gprs_sniffer/osmocom-bb git checkout origin/sylvain/burst_ind git checkout d1cb8ea9b784c7acbafbb2fdcedbdf4655c2f6f5

At this point I get

fatal: reference is not a tree: d1cb8ea9b784c7acbafbb2fdcedbdf4655c2f6f5

Next step fails too... pretty obvious...

# patch -p1 < ~/gprs_sniffer/gprs_multi.patch can't find file to patch at input line 5 [...]

Can someone drive me to the right direction? Thanks! Dario