In the last week I was hacking on OpenBSC to make GSM 12.21 Software Load usable for the ip.access nanoBTS. The difficulta was not within GSM 12.21 as Harald had it implemented for the Siemens BS11 BTS. The difficulty was that some messages need to contain paramaters and these come directly from the firmware file which ultimately means that one needs to understand the firmware file format to extract these. okteta came to rescue me and it was extremely good at doing this.

Okteta has not only the hex view one expects but also some useful utilities. Selecting a couple of bytes and the “Decoding Table” can tell you the different values in different endinanesses. So whenever I thought this is a file length, I would look into the “Decoding table”, select bytes and see how many I selected and if it could make sense, it can calculate various checksums over a selection.

Thanks a lot for Okteta, it safed my day!