From the WLC GUI:
The AP expects the .tar file to be at the root of your TFTP server. But the AP also looks for a directory named ap3g3-k9w8-tar.153-3.jpo after extraction. Ensure your TFTP server has write permissions.
Unlike monolithic .bin images, this .tar file contains multiple files that the AP’s bootloader (Uboot or ROMMON) unpacks during upgrade. Ap3g3-k9w8-tar.153-3.jpo.tar
Extracting the tarball reveals:
ap3g3-k9w8-153-3.jpo/
├── info (text file with version, build date, min WLC version)
├── ap3g3-k9w8-mx.153-3.jpo (main runtime image – LZMA compressed ELF)
├── config.txt (default regulatory domain, LED behavior)
├── version.info (detailed build IDs)
└── fpgaversion (FPGA firmware for radio PHY)
Key file – ap3g3-k9w8-mx.153-3.jpo
This is the actual IOS image, compressed (LZMA or mzip). It contains: From the WLC GUI:
The AP expects the
Do not jump directly to 15.3(3)JK – you may hit a certificate expiry bug. Use 15.3(3)JPI11 first:
The JPO suffix denotes Japan Telecom Engineering Center (MIC) certification. If you are in Japan and must comply with old Type Certification (Giteki), this specific build might be mandatory. For all other countries, use the ED or K9 variants. Key file – ap3g3-k9w8-mx
The Ap3g3 image is specifically engineered for the Cisco Aironet 2600 Series. You should only install this file on the following models:
Do not attempt to load this image on a 2700, 3700, or the legacy 1200 series. The bootloader will reject it, potentially causing the AP to enter a boot loop. The 2600 series end-of-life (EOL) was announced in 2018, but thousands remain in production in warehouses, schools, and retail environments due to their reliable 802.11n/ac Wave 1 performance.