I just found in US4064554 that the 0980 program counter and ROM page address register are both set to 0 by power-up clear circuitry.

Now I've confused myself about "program counter sequence". I interpreted that to mean execution order, but the bytes in the Star Wars patent 4270755 are in the same order as I read them off the die, which is not execution order. The 6-bit LSFR sequence has to be used to execute them.

For the 0980, are you using the 7-bit LSFR sequence that the circuit in Fig 19 generates?

0 1 3 7 15 31 63 127 126 125 123 119 111 95 62 124
121 115 103 79 30 61 122 117 107 87 46 92 56 112 97 67
6 13 27 55 110 93 58 116 105 83 38 76 24 49 98 69
10 21 43 86 44 88 48 96 65 2 5 11 23 47 94 60
120 113 99 71 14 29 59 118 109 91 54 108 89 50 100 73
18 37 74 20 41 82 36 72 16 33 66 4 9 19 39 78
28 57 114 101 75 22 45 90 52 104 81 34 68 8 17 35
70 12 25 51 102 77 26 53 106 85 42 84 40 80 32 64