Custom Firmware for Humax HDR-7500T

I am considering the purchase of a HDR-7500T for use in Australia because I still haven't ironed out all the issues of using my HDR-FOX-T2 which I brought over from the UK. I would like to let my wife have a PVR that she can use "the way we did back home", and our FOX-T2 isn't like that (yet).

However, I am a long standing and happy user of the custom firmware on the FOX-T2 and would be disappointed if I had to revert to just the factory standard behaviour on a new box. Can anyone tell me what, if anything, is possible with the 7500T?
 

Black Hole

May contain traces of nut
Can you refer the people likely to be able to advise to any relevant data? A firmware download for the HDR-7500T needs to be examined to see whether the file system is encrypted, and, presuming not, whether the validation code can be recreated so that the 7500T can be made to accept a customised set of firmware.

Even if that checks out (which, on Humax products more recent than the HDR-FOX, it does not), the amount of effort required to port the existing custom software to another product will depend on the degree of similarity. The tricks we use for achieving on-the-box decryption, for example, are exploiting oversights in the Humax design which have been rectified in later products. Thus, for the HDR-1800T/2000T, the firmware download validation is more secure so although we can read the download we can't inject our own, and the DLNA system works in a slightly different way so that decryption requires extra consideration.

The runes are not good for the HDR-7500T.

By "we" in the above, I am using the Royal "we" - not me in particular, but the collective.
 

af123

Administrator
Staff member
I've just downloaded the firmware for the 7500T and it looks very similar to that on the T2 including the way it is packaged and checksummed.
The architecture's the same too - I've just run one of the 7500T binaries on my T2 without issues.

That's good news - it should certainly be possible to enable telnet and install the package management (opkg) tool and a lot of the existing basic T2 packages should at least run on there with the right tweaks to the filesystem layout..
I don't know how much success you'll have with them though, particularly the more integrated ones.
 

Black Hole

May contain traces of nut
Well I never. That's a step in the right direction for 7500 owners then. I guess one of them will need to volunteer as a guinea pig.
 
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Brian Burch

Member
I've just downloaded the firmware for the 7500T and it looks very similar to that on the T2 including the way it is packaged and checksummed.
The architecture's the same too - I've just run one of the 7500T binaries on my T2 without issues.
Wow! Thank you very much for reacting so quickly and bravely. I wouldn't have dared flash my FOX-T2 with the 7500 firmware, but your experiment has been very valuable to me.

Thanks very much for your help.
 

Black Hole

May contain traces of nut
I doubt you would have been able to. The HDR-FOX would most likely have rejected the 7500T firmware download. af123 probably extracted the payload to have a look-see, then repackaged it for the HDR-FOX once he thought it looked OK, just to assess how similar the 7500T is to the HDR-FOX.
 
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Brian Burch

Member
Well I never. That's a step in the right direction for 7500 owners then. I guess one of them will need to volunteer as a guinea pig.
Oink Oink! (or do Guinea Pigs just snuffle?)

My secondary motive for buying a 7500T was to help me resolve the outstanding issues in my other post http://hummy.tv/forum/threads/humax-hdr-fox-t2-moved-from-uk-to-australia.5909/. I am certain the 7500T will properly auto-tune the Sunshine Coast stations, and also get the EPG times correct. It might even do series-links properly. If so, my aim was to diff the sqlite database from the 7500 against my nearly-working FOX-T2. af123's experiment leads me to hope I might simply be able to transplant the database - an experiment I am brave enough to try!
 

af123

Administrator
Staff member
I wouldn't have dared flash my FOX-T2 with the 7500 firmware, but your experiment has been very valuable to me.
Just to be clear, I didn't flash my box with the 7500 firmware, just extracted parts of the firmware and ran it on there.
It would actually be possible to flash the T2 with this firmware as it is lacking the usual system ID checks but it would also replace the bootloader which might make recovery impossible. It should be safe to repackage a copy without the bootloader and try it on a T2 but...
If you do get one, I can build you a custom update with some basic tools in it - at least you may be able to transplant the tuning database.
 
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Brian Burch

Member
Just to be clear, I didn't flash my box with the 7500 firmware, just extracted parts of the firmware and ran it on there.
It would actually be possible to flash the T2 with this firmware as it is lacking the usual system ID checks but it would also replace the bootloader which might make recovery impossible. It should be safe to repackage a copy without the bootloader and try it on a T2 but...
If you do get one, I can build you a custom update with some basic tools in it - at least you may be able to transplant the tuning database.
OK. I will go ahead with purchasing the 7500T based on the information available at this stage. I'll let you know when I have one working at home.

It would be very kind if you could help me to at least break into it and install busybox. Having most of the custom firmware would be nice, and perhaps valuable to other Australian owners, but my primary interest would be to just get root cli access.
 

Black Hole

May contain traces of nut
No need for custom firmware to do a tuning database export/import - presuming the 7500T has similar hidden service menu options as the HDR-FOX.
 
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Brian Burch

Member
I wasn't happy buying a 7500T because it seems the stocks are low in Australian shops, and the remaining units are being discounted. However, I have now bought a 7510T after discovering it is more-or-less the same unit, just with some minor cosmetic differences.

Not surprisingly, the 7510T auto-tuned the local multiplexes because it's tuning parameters for Australia tell it to use 7 mHz spacing in both the VHF and UHF wavebands. It has a secret maintenance menu that allowed me to copy channel.db, setup.db (empty) and rsv.db (one trivial record) to a usb stick. (I haven't had time to examine the channels yet).

"As usual", it arrived with back-level (1.08.22) firmware, so I usb-upgraded it to the latest from the humax web site (1.08.26). The first usb stick was ignored, even though it was empty except for the upgrade package, probably because it is usb3. My next stick was usb2 and was read, but there is a bug in the upgrade procedure. After the firmware upgrade is successfully installed, the humax reboots and immediately starts reinstalling the firmware!! It doesn't detect that the package on the stick is at the same level as the running system. After the 3rd "upgrade", I used the back-panel power switch to kill the loop during the "downloading" phase. I removed the stick, powered the humax up and was relieved to see it working normally under the new firmware.

The 7510T has a different remote control, which gave no end of fun with both the FOX-T2 and it on the same shelf! I found the tip to change the remote control frequency on this forum, but managed to misunderstand the instructions and put my T2 onto frequency zero so it lost the connection. Luckily, I could reset it to default frequency 1 and the T2 was waiting to talk to it again... then a change to channel 2 for both the remote and the humax was successful.
 

Black Hole

May contain traces of nut
My next stick was usb2 and was read, but there is a bug in the upgrade procedure. After the firmware upgrade is successfully installed, the humax reboots and immediately starts reinstalling the firmware!!
That's normal, except the HD/HDR-FOX require a manual reboot.

...but managed to misunderstand the instructions and put my T2 onto frequency zero so it lost the connection.
I didn't know that is possible!
 
Not surprisingly, the 7510T auto-tuned the local multiplexes because it's tuning parameters for Australia tell it to use 7 mHz spacing in both the VHF and UHF wavebands. It has a secret maintenance menu that allowed me to copy channel.db, setup.db (empty) and rsv.db (one trivial record) to a usb stick. (I haven't had time to examine the channels yet).

I wonder if there is some way to copy the relevant record to the HDR-Fox.
 
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Brian Burch

Member
I wonder if there is some way to copy the relevant record to the HDR-Fox.
I am not sure I understand your question. If you refer to my original thread about the FOX-T2 (http://hummy.tv/forum/threads/humax-hdr-fox-t2-moved-from-uk-to-australia.5909/), you will find a lot more background information. There are two separate "databases" under discussion:
  1. The priming database accessed via the hidden menu defines digital TV scanning parameters for all supported countries. I have not yet been able to discover its name or location. The data for the FOX-T2 in Australia is WRONG! Someone else discovered that the German parameters work for the VHF frequencies in Australia, which is appropriate for Brisbane (and probably other major cities), but the UHF channel spacing is set to 8mHz and Australia uses 7 mHz, so nothing is found during auto-tuning with transmitters that broadcast in this frequency range.
  2. The channels.db file is populated during autoscan and contains lots of information, some more important and variable than other. My other thread describes how I hacked a Brisbane-generated database to replace crucial values with those appropriate to the Sunshine Coast. It wasn't easy, but mine is 98% correct. However, if I were to do another autoscan, it would empty the database (of course, I have backups now!)
In other words, if you are in an Australian region transmitting on VHF channels, use the hidden menu to select Germany and simply auto-scan. If your local transmitter uses the UHF band, you'll have a lot of work in front of you but I am prepared to help.
 
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Brian Burch

Member
Not surprisingly, the 7510T auto-tuned the local multiplexes because it's tuning parameters for Australia tell it to use 7 mHz spacing in both the VHF and UHF wavebands. It has a secret maintenance menu that allowed me to copy channel.db, setup.db (empty) and rsv.db (one trivial record) to a usb stick. (I haven't had time to examine the channels yet).
My initial comparison shows the FOX-T2 and 7510T have very similar channels.db, but the FOX-T2 schema has extra columns in the tables TBL_SVC, TBL_TS and TBL_NET.

It seems risky to drop the 7510T channels.db onto the FOX-T2 when its firmware expects a database with more columns. I think I need to do a row-by-row comparison and then manually hack my FOX-T2 database to match.

Wouldn't it be nice to find out where the auto-tune parameters are held?! I've searched the file system on the FOX-T2, but the relevant data isn't in anything called "*.db". Perhaps it is in a plain text file somewhere, but I fear it is just coded and compiled as an array in some source module?
 

Black Hole

May contain traces of nut
I wonder if there is some way to copy the relevant record to the HDR-Fox.
I am not sure I understand your question.
I read it to mean transplanting an individual record (ie a row in one of the database tables). I have tried that, and although I can delete a row in the table or tweak some of the entries, I have not been able to add a new row or substitute a complete row.
 
OP
B

Brian Burch

Member
I read it to mean transplanting an individual record (ie a row in one of the database tables). I have tried that, and although I can delete a row in the table or tweak some of the entries, I have not been able to add a new row or substitute a complete row.
Agreed. The only thing that I've found to work is to start with a channels.db that works somewhere in the country, then replace the important fields in each row with those values which have been independently identified as locally correct, e.g. multiplex frequency, pids for audio and video, etc, as described in Black Hole's dissection thread. If it would help you, I could let you have a valid copy for Brisbane, or a nearly-correct hacked copy for the Sunshine Coast, or a (schema-subset) 7510 copy for the Sunshine Coast.
 

raeshaw

Member
I have just moved from Perth, Australia to Regional Victoria. I installed my HDR-FOX-T2 to discover that as mentioned above the Germany settings which worked fine in Perth no longer works due to local transmissions now being UHF.
Any assistance in modifying the priming database to allow 7 MHz for UHF would be appreciated.
Regards
 
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