For the old 'region only [ie no visible file system]' units there are only a few ways depending on what you need to flash, the usual being with *rgn file via Updater.exe of course as you clearly know well. Another is using SendMap to flash a supplementary detail map to region 10 [hex 0A], or invoking WebUpdater directly with cmd pmt or a bat file for some map updates such as primary detail map to region 49 [hex 31]: [Only registered and activated users can see links. ] but i guess you're already aware of that method as well.
I simply don't know any other methods not involving the above.

Certainly there are no rrgn/xrgn/ergn commands in the old unit fw which will allow using txt commands with ldr.bin on a media card in any case. It's possible to directly flash regions with just a *.bin file saved as an *.rgn [without boot.bin] as it is in many modern units but probably a little safer to do it with boot.bin included for the specific unit in the rgn file.
I consider you one of the 'old hands' bpb, I haven't got any further solving my problems detailed in P#37, do you have any solutions or suggestions for me? Please ... [Only registered and activated users can see links. ]