diff --git a/src/git_flow/git.py b/src/git_flow/git.py
index f6137a1..1224106 100644
--- a/src/git_flow/git.py
+++ b/src/git_flow/git.py
@@ -63,19 +63,13 @@ class Git:
 
     @staticmethod
     def get_first_fork_point(branch: str, env: str):
-        boundary_commits = list(
-            filter(
-                lambda c: c.startswith("-"),  # boundary commits
-                Git(
-                    "rev-list", env + "..." + branch, topo_order=True, boundary=True
-                ).lines(),
-            )
-        )
+        # Lista de commits alcanzables por el entorno (por ejemplo, dev),
+        env_commits = Git("rev-list", env + "..." + branch, first_parent=True).lines()
 
-        if not boundary_commits:
+        if not env_commits:
             raise RuntimeError("No se encontro un commit base para realizar el rebase.")
 
-        return boundary_commits[-1].removeprefix("-")
+        return Git("show", env_commits[-1] + "^", patch=False, format="%h").firstline()
 
     @staticmethod
     def _get_references(kind: str):