diff --git a/crates/xenia-cpu/src/disasm.rs b/crates/xenia-cpu/src/disasm.rs
index 6edbce1..5a98981 100644
--- a/crates/xenia-cpu/src/disasm.rs
+++ b/crates/xenia-cpu/src/disasm.rs
@@ -828,7 +828,10 @@ fn fmt_bc(instr: &DecodedInstr) -> DisasmText {
 
         if decr {
             let z = if bo & 0x02 != 0 { "z" } else { "nz" };
-            let cond_str = cond_name_opt.unwrap_or("");
+            // BO bit 4 (uncond) means CR is ignored — pure CTR-decrement branch.
+            // Without this guard, bdnz/bdz would emit a spurious `ge` suffix derived
+            // from the don't-care BI=0 / cond_true=false pair (PPCBUG-640).
+            let cond_str = if uncond { "" } else { cond_name_opt.unwrap_or("") };
             let ext_mnem = format!("bd{z}{cond_str}{a}{l}");
             let ext_ops = format!("{cr}0x{target:08X}");
             with_ext(&base_mnem, base_ops, 8, &ext_mnem, ext_ops, 8)
diff --git a/crates/xenia-cpu/tests/golden/extended_mnemonics.json b/crates/xenia-cpu/tests/golden/extended_mnemonics.json
index efb251b..6749f94 100644
--- a/crates/xenia-cpu/tests/golden/extended_mnemonics.json
+++ b/crates/xenia-cpu/tests/golden/extended_mnemonics.json
@@ -366,7 +366,7 @@
       "addr": "0x82000000",
       "mnemonic": "bc",
       "operands": "16, lt, 0x82000040",
-      "ext_mnemonic": "bdnzge",
+      "ext_mnemonic": "bdnz",
       "ext_operands": "0x82000040",
       "branch_target": "0x82000040"
     },
@@ -376,7 +376,7 @@
       "addr": "0x82000000",
       "mnemonic": "bc",
       "operands": "18, lt, 0x82000040",
-      "ext_mnemonic": "bdzge",
+      "ext_mnemonic": "bdz",
       "ext_operands": "0x82000040",
       "branch_target": "0x82000040"
     },