SPA514G: compressing the XML profile file

Question

Hi
First, thanks for any help you can give.
Serving plain text or encrypted XML config files to the SPA514G's using HTTP works well, no issues.
But if I compress the config files then the phone's do not appear to read the config they contain.  I'm using gzip on a Mac, if I list the contents of the gzipped file (gzip -lv) it shows that it uses the deflate method (RFC 1951) which I understand is the compression method that the SPA514G's support.
I have tried serving XML files that are compressed and encrypted, and ones that are just compressed without luck.  I can see on the server that the phone downloads the compressed (or compressed and encrypted) file but it does not apply the configuration it contains.
If I manually de-encrypt and decompress the XML file, a SHA1 check verifies it is identical to its source file.
Compression command: gzip --keep "${config_file}"
Encryption command: openssl enc -e -aes-256-cbc -k ${passphrase} -in "${config_file}" -out "${config_file}.enc"
Web server: Apache 2
Phone: SPA514G v1.0.0
Firmware: 7.5.6a
Customization: Open
GZip version: Apple gzip 242 (native to Mac OS X 10.10.1)
OpenSSL version: OpenSSL 0.9.8za 5 Jun 2014 (native to Mac OS X 10.10.1)
MC

Answer 1

Update: Looks like it may not be gzip after all.
A small XML file (spa-initial.xml.gz.enc <2KB decompressed) that is gzipped and encrypted works fine, syslog shows a successful resync.  This file only contains the attributes for a firmware upgrade and the provisioning profile rules.
My main XML config file (SPA514G.xml.gz.enc 212KB -> 23KB) that is gzipped and encrypted at the same time, and in the same way, as the first fails.  Syslog shows "Resync failed: corrupt file".
I would determine that the contents of SPA514G.xml.gz.enc must be at fault except it resync's successfully if the same file is delivered as raw XML or encrypted XML.
I was left wondering if its the web server (e.g. chunked transfer encoding) but that doesn't make sense either.
Compressed SPA514G.xml.gz.enc is much smaller than the raw XML so it should be easier, and the web server delivers spa-initial.xml.gz.enc fine so it can't just be the compressed content.
Just to be sure I put Tftpd32 v4.50 on a Windows PC on the same LAN as the phone, I get the same error when it tries to resync SPA514G.xml.gz.enc i.e.  "Resync failed: corrupt file".
In short:
- XML = works
- Encrypted XML = works
- Compressed XML = does not work
- Compressed & encrypted XML = does not work
Help?
MC