diff --git a/shared/actions.py b/shared/actions.py
index 6e8ae33b..e2e9995b 100644
--- a/shared/actions.py
+++ b/shared/actions.py
@@ -16,7 +16,7 @@ from export import make_json_wallet, make_summary_file, make_descriptor_wallet_e
 from export import make_bitcoin_core_wallet, generate_wasabi_wallet, generate_generic_export
 from export import generate_unchained_export, generate_electrum_wallet
 from files import CardSlot, CardMissingError, needs_microsd
-from public_constants import AF_CLASSIC, AF_P2WPKH, AF_P2WPKH_P2SH, MAX_TXN_LEN_MK4
+from public_constants import AF_CLASSIC, AF_P2WPKH, AF_P2WPKH_P2SH
 from glob import settings
 from pincodes import pa
 from menu import start_chooser, MenuSystem, MenuItem
@@ -1511,7 +1511,7 @@ async def qr_share_file(_1, _2, item):
 
     while 1:
         txid = None
-        fn = await file_picker(min_size=10, max_size=MAX_TXN_LEN_MK4, taster=is_suitable)
+        fn = await file_picker(min_size=10, max_size=MAX_TXN_LEN, taster=is_suitable)
         if not fn: return
 
         basename = fn.split('/')[-1]
diff --git a/shared/bbqr.py b/shared/bbqr.py
index 61a90fb9..b7d8b95c 100644
--- a/shared/bbqr.py
+++ b/shared/bbqr.py
@@ -6,6 +6,7 @@ import utime, uzlib, ngu
 from utils import problem_file_line
 from exceptions import QRDecodeExplained
 from ubinascii import unhexlify as a2b_hex
+from version import MAX_TXN_LEN
 
 b32encode = ngu.codecs.b32_encode
 b32decode = ngu.codecs.b32_decode
@@ -328,14 +329,12 @@ class BBQrPsramStorage(BBQrStorage):
     def alloc_buf(self, upper_bound):
         # using first part of PSRAM
 
-        from public_constants import MAX_TXN_LEN_MK4
-
-        if upper_bound >= MAX_TXN_LEN_MK4:
+        if upper_bound >= MAX_TXN_LEN:
             raise QRDecodeExplained("Too big")
 
         # If data is compressed, write tmp (compressed) copy into top half of PSRAM
         # and we'll put final, decompressed copy at zero offset (later)
-        self.psr_offset = MAX_TXN_LEN_MK4 if self.hdr.encoding == 'Z' else 0
+        self.psr_offset = MAX_TXN_LEN if self.hdr.encoding == 'Z' else 0
 
         self.buf = True
 
@@ -394,7 +393,6 @@ class BBQrPsramStorage(BBQrStorage):
         from glob import PSRAM, dis
         from uzlib import DecompIO
         from io import BytesIO
-        from public_constants import MAX_TXN_LEN_MK4
 
         dis.fullscreen('Decompressing...')
 
@@ -414,7 +412,7 @@ class BBQrPsramStorage(BBQrStorage):
                 buf += here
                 ln = len(buf) & ~3
 
-                if off+ln > MAX_TXN_LEN_MK4:
+                if off+ln > MAX_TXN_LEN:
                     # test with: `yes | dd bs=1000 count=2700 | bbqr make - | pbcopy`
                     raise QRDecodeExplained("Too big")
                 
diff --git a/shared/version.py b/shared/version.py
index a351b54f..3fab78a9 100644
--- a/shared/version.py
+++ b/shared/version.py
@@ -4,7 +4,8 @@
 #
 # REMINDER: update simulator version of this file if API changes are made.
 #
-from public_constants import MAX_TXN_LEN, MAX_UPLOAD_LEN
+from public_constants import MAX_TXN_LEN_MK4 as MAX_TXN_LEN
+from public_constants import MAX_UPLOAD_LEN_MK4 as MAX_UPLOAD_LEN
 
 def decode_firmware_header(hdr):
     from sigheader import FWH_PY_FORMAT
@@ -76,7 +77,6 @@ def probe_system():
     # run-once code to determine what hardware we are running on
     global hw_label, has_608, is_factory_mode, is_devmode, has_psram, is_edge
     global has_se2, mk_num, has_nfc, has_qr, num_sd_slots, has_qwerty, has_battery, supports_hsm
-    global MAX_UPLOAD_LEN, MAX_TXN_LEN
 
     from sigheader import RAM_BOOT_FLAGS, RBF_FACTORY_MODE
     import ckcc, callgate, machine
@@ -121,11 +121,6 @@ def probe_system():
     # what firmware signing key did we boot with? are we in dev mode?
     is_devmode = get_is_devmode()
 
-    # increase size limits for mk4
-    from public_constants import MAX_TXN_LEN_MK4, MAX_UPLOAD_LEN_MK4
-    MAX_UPLOAD_LEN = MAX_UPLOAD_LEN_MK4
-    MAX_TXN_LEN = MAX_TXN_LEN_MK4
-
 probe_system()
 
 # EOF