VOGONS


First post, by TheMLGladiator

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I'm having an issue installing Jetfighter II from floppy. Whenever I try and run the installer on disk A the system hangs on a blinking cursor. I have tried installing with and without himem and emm386, disabled cd rom drivers, tried again in 86Box emulating a 486DX.

Reply 1 of 4, by eddman

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Try an 8088/8086 system.

EDIT: It SHOULD work on 386 and 486. Yea, something is off.

Reply 2 of 4, by ripsaw8080

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Earlier versions of some Velocity games have self-decrypting executables that use prefetch tricks on the CPU as an anti-debugger strategy. The prefetch tricks do not work correctly on Pentium and later processors, and some emulators don't emulate the necessary prefetch behavior. In DOSBox you would use the cputype=386_prefetch setting.

You might try looking for patches or updates to later versions, as there were cases of "Pentium fixes" that removed the encryption and associated prefetch tricks. AFAICT, the last release version of Jetfighter II is v1.1B

Reply 3 of 4, by TheMLGladiator

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ripsaw8080 wrote on 2026-08-03, 23:12:

Earlier versions of some Velocity games have self-decrypting executables that use prefetch tricks on the CPU as an anti-debugger strategy. The prefetch tricks do not work correctly on Pentium and later processors, and some emulators don't emulate the necessary prefetch behavior. In DOSBox you would use the cputype=386_prefetch setting.

You might try looking for patches or updates to later versions, as there were cases of "Pentium fixes" that removed the encryption and associated prefetch tricks. AFAICT, the last release version of Jetfighter II is v1.1B

Thanks, 386_prefetch seems to work in DOSBox. Was that last release ever distributed as a patch? I'm having trouble finding much on this game online.

Reply 4 of 4, by ripsaw8080

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I don't know if it was possible to get v1.1B through patching. The only patch that seems to be available online is v1.05: https://www.patches-scrolls.de/patch/2270/7/ -- not sure if it addresses the issue with later CPUs.