diff --git a/src/p_lx_elf.cpp b/src/p_lx_elf.cpp
index a237794a..eea5540a 100644
--- a/src/p_lx_elf.cpp
+++ b/src/p_lx_elf.cpp
@@ -183,8 +183,11 @@ bool PackLinuxI386elf::canPack()
         if (j >= 14)
             return false;
         if (phdr->PT_LOAD == phdr->p_type) {
-            if (phdr->p_offset!=0)
+            if (phdr->p_offset != 0)
+            {
+                throwCantPack("invalid Phdr p_offset; try `--force-execve'");
                 return false;
+            }
             exetype = 1;
             break;
         }
diff --git a/src/p_lx_exc.cpp b/src/p_lx_exc.cpp
index a56a8157..941e5f4a 100644
--- a/src/p_lx_exc.cpp
+++ b/src/p_lx_exc.cpp
@@ -95,11 +95,10 @@ int PackLinuxI386::checkEhdr(const Elf_LE32_Ehdr *ehdr) const
 {
     const unsigned char * const buf = ehdr->e_ident;
 
-    // NOTE: ELF executables are now handled by p_lx_elf.cpp.
+    // info: ELF executables are now handled by p_lx_elf.cpp
     if (memcmp(buf, "\x7f\x45\x4c\x46\x01\x01\x01", 7)) // ELF 32-bit LSB
         return -1;
 
-    // FIXME: add special checks for uncompresed "vmlinux" kernel
     // now check the ELF header
     if (!memcmp(buf+8, "FreeBSD", 7))                   // branded
         return 1;
@@ -109,6 +108,12 @@ int PackLinuxI386::checkEhdr(const Elf_LE32_Ehdr *ehdr) const
         return 3;
     if (ehdr->e_version != 1)                           // version
         return 4;
+    if (ehdr->e_phnum < 1)
+        return 5;
+
+    // FIXME: add special checks for uncompresed "vmlinux" kernel
+    // FIXME: add special checks for other ELF i386 formats, like
+    //        NetBSD, OpenBSD, Solaris, ....
 
     // success
     return 0;