I'm vaguely aware that the Exult project has a computer program (ucxt?) that can disassemble Usecode (the script for usable objects such as NPCs in conversation) to a somewhat human-readable form. I suppose that someone with enough interest and technical ability and time on their hands could use that or some other tool to disassemble Jaana's code and see what exactly is checked in that part of her conversation to determine whether she is able to do healing.

Some day I'd like to make a web-based Usecode viewer / editor.. some day.

It might be even cooler to modify NPC behavior to enable Jaana to cast healing spells during combat.

edit: I've since found the cause of this issue and patched U7BG to prevent the bug from occurring; see my posts below.

Could be an Exult issue. I haven’t experienced this playing the normal version. Every time I used Exult I ran into issues, so I eventually stopped using it. One thing that always ended up happening to me was objects (buildings even sometimes) disappearing. My guess was always that the game has a total object limit which is blown out by the tailor in Britain endlessly adding more items to the game (another bug). So beware!

As far as I know they solved that bug long ago though. :) It's not been happening to me in their latest releases.
Although I have unfortunately been experiencing crashes in TBG in their recent releases, which forces me to save often.
Also, that item limit also happens in vanilla if you go out of your way to create lots of items (by, for example, winning tons of gold at the casino).



As for 6502's problem: You mentioned playing vanilla, so not an Exult issue at least.
Have you tried removing her from the party, waiting a full day, then inviting her back in?

Unfortunately, Jaana is the only healer who will join your party.

I got curious enough to run the Exult Usecode disassembler, ucxt, on Jaana's script.

It turns out that Jaana's healing dialogue checks and sets game timer 10 (0xA). The state of this timer is stored in the file GAMETIMK.DAT in the saved game (e.g. GAMEDAT/GAMETIMK.DAT for the default / last save).

I have successfully set this timer (and skipped past Jaana's healing cooldown) by doing this:
- save and exit from Ultima VII
- hex-edit the file GAMEDAT\GAMETIMK.DAT, setting the contents (six bytes) to 00 00 00 00 01 00
- launch Ultima VII again and Journey Onward

Are you familiar with hex-editing and able to hex-edit this file? If not, I could try to send you a copy of the edited file...

Exult is irrelevant to this, other than that i used a tool developed by them to analyze the (original) game's script.

The hex-editing solution (or workaround) i proposed is entirely relevant to the GOG version of the game; that is what i tested it on.

If you do try what i suggested, please let me know what results you get. Also, there's a rare chance that you may have to sleep again for up to 5 hours (in game, not in real life) after applying the steps.

My understainding is that the Uecode, which is the game's scripting language, is the same for both versions. Exult just has a Usecode interpreter that interprets this language, so anything related to the Usecode *should* be the same (barring a bug in the interpreter).

(This means that, for example, the effects of training should be the same, since Usecode handles that. However, the HP/MP regen each hour is not, and as a result is different last I checked.)

I'm glad that the workaround worked for you. I have now fixed the bug in U7BG that causes this issue in my UltimaHacks, which you can apply if you want a permanent fix.

https://github.com/JohnGlassmyer/UltimaHacks

Digging into the game's code, I found this inconsistency: when trying to calculate the number of hours that have elapsed since a given timer was set, it uses a day-of-the-week number (which wraps around to 0 every 7 days) rather than the absolute day number.

So, for example, Jaana's healing is supposed to be unavailable for 5 hours after the last use, but if you use her healing at noon on Saturday then it would still be unavailable at noon on the following Thursday because the game would think that -2 (negative two) days had passed, which would be "less than" the required 5 hours. And if you were unlucky enough to use her healing less than 5 hours before the end of the in-game week, then there would never be a subsequent time when her healing would be available.

I've patched U7BG to use absolute day number instead in this calculation, and verified that this prevents the issue from occurring.

U7SI does not have the same issue; it already uses absolute day number in the corresponding calculation.

Nice job!