FRAM71B installation

[Hans Brueggemann]

the HP-71B declares/recognizes a freed port by the "3BDDDDDE" in that particular port's header. an attempt to claim that port back into main memory will fail if that header is not found. this can happen when F_addresses are accidentally being swapped or when jumper CN2-2 is set. to hunt down the freed port in question, a PEEK$ (Port_begin_H_adr$, 16) done on each of the RAM modules' start address should reveal the port. however, the situation is a bit tricky here, because of E4 being only 16 kB. so, this is my best guess on how the HP-71B would arrange the memory:

Code:

H_0x30000: 18
H_0x40000: 19
H_0x50000: 1A
H_0x60000: 9B
H_0x70000: E4

it is also a good idea to experimentally configure the unused F_Blocks as additional RAM and then check them individually for IRAM headers.