diff --git a/proxyclient/m1n1/hv/__init__.py b/proxyclient/m1n1/hv/__init__.py
index 6c87976d7..1f223d97b 100644
--- a/proxyclient/m1n1/hv/__init__.py
+++ b/proxyclient/m1n1/hv/__init__.py
@@ -1757,7 +1757,12 @@ def load_raw(self, image, entryoffset=0x800, use_xnu_symbols=False, vmin=0):
         if use_xnu_symbols == True:
             self.sym_offset = vmin - guest_base + self.tba.phys_base - self.tba.virt_base
 
-        self.iface.writemem(guest_base + self.bootargs_off, BootArgs.build(self.tba))
+        if self.tba.revision <= 1:
+            self.iface.writemem(guest_base + self.bootargs_off, BootArgs_r1.build(self.tba))
+        elif self.tba.revision == 2:
+            self.iface.writemem(guest_base + self.bootargs_off, BootArgs_r2.build(self.tba))
+        elif self.tba.revision == 3:
+            self.iface.writemem(guest_base + self.bootargs_off, BootArgs_r3.build(self.tba))
 
         print("Setting secondary CPU RVBARs...")
         rvbar = self.entry & ~0xfff
diff --git a/proxyclient/m1n1/proxy.py b/proxyclient/m1n1/proxy.py
index 8428c8f5b..9a89fb61f 100644
--- a/proxyclient/m1n1/proxy.py
+++ b/proxyclient/m1n1/proxy.py
@@ -721,6 +721,10 @@ def reload(self, addr, *args, el1=False):
                 self.request(self.P_CALL, addr, *args, reboot=True)
     def get_bootargs(self):
         return self.request(self.P_GET_BOOTARGS)
+    def get_bootargs_rev(self):
+        ba_addr = self.request(self.P_GET_BOOTARGS)
+        rev = self.read16(ba_addr)
+        return (ba_addr, rev)
     def get_base(self):
         return self.request(self.P_GET_BASE)
     def set_baud(self, baudrate):
diff --git a/proxyclient/m1n1/proxyutils.py b/proxyclient/m1n1/proxyutils.py
index 9b60063f8..78569dd74 100644
--- a/proxyclient/m1n1/proxyutils.py
+++ b/proxyclient/m1n1/proxyutils.py
@@ -44,9 +44,14 @@ def __init__(self, p, heap_size=1024 * 1024 * 1024):
         self.iface = p.iface
         self.proxy = p
         self.base = p.get_base()
-        self.ba_addr = p.get_bootargs()
-
-        self.ba = self.iface.readstruct(self.ba_addr, BootArgs)
+        (self.ba_addr, self.ba_rev) = p.get_bootargs_rev()
+
+        if self.ba_rev <= 1:
+            self.ba = self.iface.readstruct(self.ba_addr, BootArgs_r1)
+        elif  self.ba_rev == 2:
+            self.ba = self.iface.readstruct(self.ba_addr, BootArgs_r2)
+        elif  self.ba_rev == 3:
+            self.ba = self.iface.readstruct(self.ba_addr, BootArgs_r3)
 
         # We allocate a 128MB heap, 128MB after the m1n1 heap, without telling it about it.
         # This frees up from having to coordinate memory management or free stuff after a Python
diff --git a/proxyclient/m1n1/tgtypes.py b/proxyclient/m1n1/tgtypes.py
index 9081c8df0..1e47c28dd 100644
--- a/proxyclient/m1n1/tgtypes.py
+++ b/proxyclient/m1n1/tgtypes.py
@@ -1,9 +1,35 @@
 # SPDX-License-Identifier: MIT
 from construct import *
 
-__all__ = ["BootArgs"]
+__all__ = ["BootArgs_r1", "BootArgs_r2", "BootArgs_r3"]
 
-BootArgs = Struct(
+BootArgs_r1 = Struct(
+    "revision"              / Hex(Int16ul),
+    "version"               / Hex(Int16ul),
+    Padding(4),
+    "virt_base"             / Hex(Int64ul),
+    "phys_base"             / Hex(Int64ul),
+    "mem_size"              / Hex(Int64ul),
+    "top_of_kernel_data"    / Hex(Int64ul),
+    "video" / Struct(
+        "base"      / Hex(Int64ul),
+        "display"   / Hex(Int64ul),
+        "stride"    / Hex(Int64ul),
+        "width"     / Hex(Int64ul),
+        "height"    / Hex(Int64ul),
+        "depth"     / Hex(Int64ul),
+    ),
+    "machine_type"          / Hex(Int32ul),
+    Padding(4),
+    "devtree"               / Hex(Int64ul),
+    "devtree_size"          / Hex(Int32ul),
+    "cmdline"               / PaddedString(256, "ascii"),
+    Padding(4),
+    "boot_flags"            / Hex(Int64ul),
+    "mem_size_actual"       / Hex(Int64ul),
+)
+
+BootArgs_r2 = Struct(
     "revision"              / Hex(Int16ul),
     "version"               / Hex(Int16ul),
     Padding(4),
@@ -28,3 +54,29 @@
     "boot_flags"            / Hex(Int64ul),
     "mem_size_actual"       / Hex(Int64ul),
 )
+
+BootArgs_r3 = Struct(
+    "revision"              / Hex(Int16ul),
+    "version"               / Hex(Int16ul),
+    Padding(4),
+    "virt_base"             / Hex(Int64ul),
+    "phys_base"             / Hex(Int64ul),
+    "mem_size"              / Hex(Int64ul),
+    "top_of_kernel_data"    / Hex(Int64ul),
+    "video" / Struct(
+        "base"      / Hex(Int64ul),
+        "display"   / Hex(Int64ul),
+        "stride"    / Hex(Int64ul),
+        "width"     / Hex(Int64ul),
+        "height"    / Hex(Int64ul),
+        "depth"     / Hex(Int64ul),
+    ),
+    "machine_type"          / Hex(Int32ul),
+    Padding(4),
+    "devtree"               / Hex(Int64ul),
+    "devtree_size"          / Hex(Int32ul),
+    "cmdline"               / PaddedString(1024, "ascii"),
+    Padding(4),
+    "boot_flags"            / Hex(Int64ul),
+    "mem_size_actual"       / Hex(Int64ul),
+)
diff --git a/proxyclient/tools/chainload.py b/proxyclient/tools/chainload.py
index 2639e5314..22125132b 100755
--- a/proxyclient/tools/chainload.py
+++ b/proxyclient/tools/chainload.py
@@ -17,7 +17,7 @@
 args = parser.parse_args()
 
 from m1n1.setup import *
-from m1n1.tgtypes import BootArgs
+from m1n1.tgtypes import BootArgs_r1, BootArgs_r2, BootArgs_r3
 from m1n1.macho import MachO
 from m1n1 import asm
 
@@ -113,7 +113,12 @@
     tba.virt_base = 0xfffffe0010000000 + (tba.phys_base & (32 * 1024 * 1024 - 1))
     tba.devtree = u.ba.devtree - u.ba.virt_base + tba.virt_base
 
-iface.writemem(image_addr + bootargs_off, BootArgs.build(tba))
+if tba.revision <= 1:
+    iface.writemem(image_addr + bootargs_off, BootArgs_r1.build(tba))
+elif tba.revision == 2:
+    iface.writemem(image_addr + bootargs_off, BootArgs_r2.build(tba))
+elif tba.revision == 3:
+    iface.writemem(image_addr + bootargs_off, BootArgs_r3.build(tba))
 
 print(f"Copying stub...")