Merge pull request #54 from Zektopic/bolt/optimize-string-join-11477192544837518008

⚡ Bolt: Replace deprecated string.join with native str.join in jungo-image.py

Author: manupawickramasinghe

.jules/bolt.md

@@ -47,3 +47,6 @@
 ## 2025-01-20 - [Python CRC32 Chunked File I/O in sercomm-kernel-header]
 **Learning:** In `scripts/sercomm-kernel-header.py`, reading entire kernel and rootfs files into memory with `.read()` and `.read(rootfs_size)` causes excessive memory bloat (O(N) complexity). Memory limit issues can easily happen on large firmware images.
 **Action:** Use an incremental CRC approach over chunked reads for large files (`crc = binascii.crc32(chunk, crc)`). This maintains O(1) memory usage, improving efficiency and memory footprint.
+## 2026-04-11 - [string.join deprecation and performance issue]
+**Learning:** In Python 3, string.join() was removed. The native ''.join(iterable) is the correct alternative, and also yields a performance improvement.
+**Action:** Replace string.join with ''.join in the codebase where encountered.

scripts/flashing/jungo-image.py

@@ -29,7 +29,6 @@
 import getopt
 import getpass
 import telnetlib
-import string
 import binascii
 import socket
 import _thread
@@ -140,7 +139,8 @@ def image_dump(tn, dumpfile):
                     print("Format error: %x != %x"%(a,count))
                     sys.exit(2)
                 count += 16
-                f.write(binascii.a2b_hex(string.join(s[1:],'')))
+                # Optimization: Use native ''.join instead of deprecated string.join for better performance and Python 3 compatibility
+                f.write(binascii.a2b_hex("".join(s[1:])))
         tn.read_until(">",1)
 
     f.close()