The easiest choice now is to use the Toppy.org.uk Firmware Loader, which will install the most up-to-date, pre-patched firmware for your model. This sterling work comes from the MyStuff team. There is also a firmware loader especially for MyStuff (incorporating extra patches that MyStuff is compatible with) — the firmwares recommended for MyStuff can be downloaded separately from here.

Unofficial firmwares are also available from the Toppy.org.uk site. The main, public list of firmwares contains Official (unpatched) firmwares including some beta releases not available elsewhere, but they are now a little out of date. That list is also a bit misleading since better firmwares are available to registered members in the member area (it's not entirely obvious, but you will need to register with the forums part to gain access to that area.

• TF5800 — TF5800NITfix1365 (patches) or the unpatched TF5800-5.13.65beta
• TF5800t — specific one not available (but see here)
• TF5810 — TF5810UnofficialUpdatePackV3 (patches)

— TF5810 —

TF5810 owners have little choice but to use a 5.15.X firmware, which is the same as the corresponding (and not recommended) TF5800 5.14.X firmware but with changes for support of the TF5810-specific hardware (the HDMI up-scaler and the better Front Panel). The main problems are discussed here. The current best starting point is 5.15.09+ plus any extra patches described in that thread.

— TF5800t —

For some reason, Topfield decided to give this face-lift version a new SysID (i.e. it will show "C458" on the Front Panel when booting, rather than the "C456" of the normal TF5800), even though the hardware is identical and the unit is otherwise completely compatible with the normal TF5800 (in fact, some normal TF5800 models are also believed to have shipped with this 458 SysID).

Any TF5800 firmware will work on the TF5800t, but the different SysID prevents direct use and may also confuse some TAPs. The latter is easily remedied by the SysID 456 [Sy] patch, but the former requires using VegaPack to alter the firmware (.tfd) file to SysID 458 or using HDFW to force on the firmware (including aXeL [Xl]).

— Recommendations —

The Official firmwares are (currently) way out of date and not recommended at all. And, in general, the 5.14.X firmwares are not recommended because Topfield's implementation of the Freeview+ system (including Series Links and Accurate Recording) is somewhat lacking — something that will become painfully apparent to most users. See here for more details.

In order of simplicity, these are my recommendations:

• For most users running a Windows PC, the best choice is to use the Toppy.org.uk Firmware Loader.
• If you are using no TAPs at all, or just MyStuff, or TAPs that are also compatible with the [De] and [Re] patches, then you can download the MyStuff Recommended Firmware for your model of Toppy from here (or you may want to use the special MyStuff Firmware Loader).
• Next best would be the Semi-Official firmwares, i.e. 5.13.65N for the TF5800 and TF5800t, or 5.15.09+ for the TF5810.
• For the TF5800 and TF5800t, use the unpatched 5.13.65 and add the patches you want/need, especially all the Essential and Bug Fixes.
• For the TF5810, use 5.15.09+ and keep up with the latest developments.