HP-21MX bootstrapping?

Tim Riker wrote: I would just suggest that you add a log/history comment with date/name under my creation date/name comment to indicate changes and to distinguish it from my original. The format is documented (or at least my understanding of it) at the beginning of the above-linked file, based on my disassembly of the machine code in the HP manual. Look at the other two period BBLs on my site for comparison. Actually, to be a little more accurate in terminology: the BBL (Basic Binary Loader) bootstrap programs read data in ABS (ABSolute-address load record) format. BBL & ABS date from the original 2116 systems. Originally the BBLs were manually toggled into core at the top of memory. ABS format (.abs) does require a fully-transparent, 8-bit, binary datapath. There was also a relocatable record format usable at later stages in the bootstrap. I believe the ABS format, with new BBLs for new devices, continued to be used with the later 2100 systems but others can comment on that better than I can. I will hazard a guess that if an HP serial-line loader for the 2100 shows up it may look a lot like what I'm describing in modifying the old teleprinter loader. Didn't you have a 2116B with a broken aluminum frame, or was that someone else?