# RE notes — EU4 1.37.5 loading tip / screen cycle mechanism > Static-analysis findings on `eu4.exe` 1.37.5 (build 2024-10-03, > SHA-256 `9ad3efe1af169f40ee577f9dae5debbc87af6fb8b5450fb345ebf110dc4d771a`). > The goal of this file is to give the next maintainer enough breadcrumbs > to skip the dead-ends and jump straight to the cycle function once > Ghidra analysis finishes. ## Target binary ``` C:\Program Files (x86)\Steam\steamapps\common\Europa Universalis IV\eu4.exe ``` | Property | Value | |------------------------|--------------------------------------------------------| | Size | 38,462,504 bytes (36.7 MiB) | | SHA-256 | `9ad3efe1af169f40ee577f9dae5debbc87af6fb8b5450fb345ebf110dc4d771a` | | Version | `release_1.37.5` (rev `835bfdf8ca24c291a1b3f1b5bc72d47e7df1ae18`) | | PE timestamp | 2024-10-03 17:58:17 | | Format | PE32+ x86-64, 7 sections, no UPX | | Linker | MSVC 14.29 (VS 2019 16.9–16.10) | | ImageBase | `0x140000000` | | PDB | none shipped (path string `eu4\eu4\outputdir_windows\eu4.pdb` only) | | .text VMA / file | `0x140001000` / `0x00000400` size `0x1B64D78` | | .rdata VMA / file | `0x141B66000` / `0x01B65200` size `0x44999A` | | .data VMA / file | `0x141FB0000` / `0x01FAEC00` size `0x384400` | ## Loading-screen string table A single string block in `.rdata` (file offset `0x1D62B4B` – `0x1D62B9C`) contains every name the loading-screen code looks up by string: | File offset | VMA | Bytes / purpose | |-------------|----------------|----------------------------------------------------------------| | `0x1D62B4B` | `0x141D62B4B` | `"load_screen2\0"` — sprite name `bg_load_screen2` (status bg) | | `0x1D62B6C` | `0x141D62B6C` | `"tip\0"` — the loading-tip windowType | | `0x1D62B70` | `0x141D62B70` | `"load_screen\0"` — the root load_screen windowType | | `0x1D62B80` | `0x141D62B80` | `"LOADING_TIP_\0"` — localization key namespace (no xref; built dynamically via `format` + integer) | | `0x1D62B88` | `0x141D62B88` | `"status\0"` — the loading-status windowType | > None of `loading_tip`, `LOADING_TIP`, `loading_screen`, `LoadingScreen`, > `getLocalization`, `getLocalisation`, `resolveKey`, `Timer`, `tick`, > `interval`, `next_tip`, `setTextFromKey`, `set_loading_tip` appear > as strings anywhere in the binary. The localization keys are built > with `format("LOADING_TIP_{}", i)` at runtime, which is why > `grep "LOADING_TIP_"` finds only the namespace literal and zero > references. ## Loading-screen construction (`sub_141174F50`) **Entry**: `0x141174F50` (image-base + offset, file offset = VMA − `0x140000000` = `0x1D74F50`). Called from two places, both inside the same TU: - `0x1411749E9` — first call site - `0x141174EE2` — second call site The function: 1. Allocates a 32-byte string buffer (`call 0x1400950B0` is `operator new`). 2. Copies a 16-byte structure from `.rdata` into it, then a 2-byte and 1-byte tail. 3. Calls `vtable[0x120](rdi, &local)` (string-keyed registration or `addChildByName`). 4. After allocation, sets `[rbx+0x100] = 1` (or `0`) based on `[rip+0x12b6d79] + 0x28b` — almost certainly an `is_loading_synchronous` / `is_replay` flag. 5. Calls `lea rdx, [rip+0xbedadd]` → `"load_screen"` and `call [rax+0x98]` (a `findChildByName` virtual). 6. The branch at `0x14117509C`: ``` cmp [rbp+0x28], 1 je 0x1411750CA ; ironman/replay branch cmp [rip+0x11caea6], 0 ; probably online check jne 0x1411750CA mov rdx, [rbx] mov rcx, rbx call [rdx+0x88] ; vtable[0x88] ``` The `vtable[0x88]` and `vtable[0x90]` are the two `setVisible` / `setActive` overloads, depending on `[rbp+0x28] == 1`. This is the **construction / activation** path, not the cycling path. ## Status-text updater (`sub_141174840`) **Entry**: `0x141174840`. 1. `call 0x141172B20` — likely the `LoadingScreen::onEnter` initializer. 2. `lea rdx, [rip+0xbee32b]` → `"status"`; `call [rax+0xB8]` = `findChildByName("status")`. 3. The found child at `[rax+0xC8]` is the `text` instantTextBox inside `status`. 4. Then the function appends a fixed sequence of characters to the textbox: ``` 0x141174893: mov dl, 0x5C '\' 0x14117489D: mov dl, 0x2F '/' 0x1411748A7: mov dl, 0x3A ':' 0x1411748B1: mov dl, 0x2A '*' 0x1411748BB: mov dl, 0x3F '?' 0x1411748C5: mov dl, 0x3C '<' 0x1411748CF: mov dl, 0x3E '>' 0x1411748D9: mov dl, 0x7C '|' ``` These are the **classic ASCII spinner glyphs**. The function re-renders them in sequence. This is the *status* progress indicator, **not** the tip cycler. 5. Then `lea rdx, [rip+0xbee2a1]` → `0x141D62B94` (some other name, the bytes are immediately after `"status\0"` in the string table) and `call [rax+0x68]`. The function then tail-calls `jmp [rax+0x8]` to a setter. The status updater is driven by an outer loop — search for callers of `0x141174840` to find the per-frame tick. ## Tip cycle function (NOT YET LOCATED) What we know it must do: 1. Find the `"tip"` windowType child of the load_screen GUI (`findChildByName("tip")` or via the child at offset 0xC8). 2. Increment an internal `Timer` member every frame. 3. When `elapsed >= interval`, pick a random `i` in `[0, 67)`, build the key `"LOADING_TIP_" + i`, and call `setText(localizedKey)` on the tip textbox. 4. Reset the timer to 0. The `"tip\0"` C-string exists at VMA `0x141D62B6C` but **has zero xrefs in the disassembly** as a literal. The function therefore either: - Uses a hardcoded offset / index instead of a string lookup (e.g. `getNthChild(1)` of the load_screen root), or - Builds the `"tip"` name dynamically via `format` or string concat. **Next step (with Ghidra decompiler):** decompile the call graph of `sub_141174F50` (the load_screen setup) and look for the per-frame update path. The cycling function is somewhere in that graph. ## Timer constants table At VMA `0x141DC1750` (file offset `0x1DC0950`) is a 16-entry table of `double` constants used by the engine for UI timers: | VMA | Value | Likely use | |------------------|-------------|---------------------------------------------| | `0x141DC1750` | `4.0` | fast spinner tick | | `0x141DC1758` | `5.0` | | | `0x141DC1760` | `8.0000019` | (FP rounding artifact, paired with next) | | `0x141DC1768` | `8.0` | **prime suspect for tip cycle interval** | | `0x141DC1770` | `9.6` | (mid-game tick?) | | `0x141DC1778` | `10.0` | slow spinner / pause | | `0x141DC1780` | (garbage) | (denormal / uninitialised) | | `0x141DC1788` | `15.0` | tooltip dwell | | `0x141DC1790` | `20.0` | | | `0x141DC1798` | `30.0` | | | `0x141DC17A0` | `40.0` | | | `0x141DC17A8` | (garbage) | | | `0x141DC17B0` | `100.0` | | | `0x141DC17B8` | `180.0` | | | `0x141DC17C0` | `200.0` | | The `8.0` value at `0x141DC1768` is referenced from 11 disassembly sites. Most are *not* the tip cycler (verified: 0x14081D83A is part of a `0x14081D...` per-frame update, 0x14182CC75 is a graphics normalize function). The true cycle call site is one of the remaining xrefs and will be identified by the call graph in the Ghidra decompile. **Patch candidates** (most likely first): - `0x1DC0968` (VMA `0x141DC1768`) — the `8.0` literal itself. Patch: overwrite 8 bytes with the user's `tip_interval_seconds` as a `double`. 8-byte write. - Alternatively, if the cycle function takes the value via `movsd xmm1, [rip+offset]` to the constant, we patch the `movsd` to load from a writable .data cell the patcher initializes at runtime. - A third option: NOP the `jbe` / `jge` after the elapsed-time comparison in the cycle function to slow the cycle to "never". ## What remains to do (Ghidra pass) 1. Open `eu4.exe` in `C:\tools\ghidra_12.1.2_PUBLIC\ghidraRun.bat`. 2. Search → For Strings → `"load_screen"`, `"tip"`, `"status"`, `"LOADING_TIP_"`. 3. For each, jump to the xref and decompile the containing function. 4. The tip cycler will be a function that: - Reads `[rdi+0x30]` (vtable), looks up the `"tip"` child via vtable[0xB8] (or a sibling lookup). - Has a `Timer` member (look for `add`, `sub`, `cmp` with `8.0` and a `jb`/`ja` that conditionally calls `setText`). 5. Record the VMA + file offset of the comparison constant, and identify the byte pattern that uniquely matches across `1.37.5.x` builds. The patcher will use this pattern for `--rescan` after game updates. ## Ironman / achievement bypass (Phase 2 task, partially found) The MD5-based integrity check is at VMA range **`0x1410F78B0` – `0x1410F8666`**, with the hash init at **`0x1410F80B8`** (`mov DWORD PTR [rbp+0xb0], 0x67452301` — the standard MD5 init constant). The function: 1. Sets up the timer / state at `0x1410F8084` (`movsd xmm2, [rip+…]` → `8.0`, passed as the third arg of a virtual call at `0x1410F808E: call QWORD PTR [rax+0x10]`). 2. Computes the MD5 hash of the game state at `0x1410F84B0: call 0x1410DD830`. 3. Uploads / records the hash via `0x1410F8573: call 0x1416554B0` (with at least 6 string / data arguments, the most likely "write to save header + sync to Paradox" call site). 4. Sets a global flag at `0x1410F85FA` (`mov DWORD PTR [rip+0x1247877 + 0x747c], 1`) — almost certainly `is_saving_ironman = true`. 5. Continues into the "save complete" path (call to `0x1410F864E: call r8` for `vtable[0x10]`, which is the `onSaveComplete` callback). ### Ironman patch candidates (to verify in next pass) | VMA | Action | |-----------------|------------------------------------------------------------------------| | `0x1410F84B0` | 5-byte call `0x1410DD830` (MD5 compute). NOP it. | | `0x1410F8573` | 5-byte call `0x1416554B0` (hash upload). NOP it. | | `0x1410F85FA` | 10-byte `mov DWORD PTR [...+0x747c], 1`. Patch to `mov [...+0x747c], 0` to defeat "this is ironman" state. | | `0x1410F80B8`–`0x1410F80C7` | 16-byte MD5 init constants. Wipe with NOPs. | Any one of these patches alone is enough to disable a single link in the chain; for full ironman-bypass, do all three. The `--revert` path must restore the original bytes. ### Hash-upload destination string The 6 string arguments to `0x1416554B0` at `0x1410F8500`–`0x1410F8573` include: - `0x141D5C438` — likely a Paradox account ID or session token (used at `0x1410F84F3: lea rdx, [rip+0xc63f3e]`). - A save-header key at `0x141D228B8` (used at `0x1410F799F`). - A field at `0x141C4238C` (used at `0x1410F86E0` — to be confirmed). These are good search anchors for the Ghidra xref pass.