when i open bg toolset there's no prompt to enable flash - just a screen with my firmware, vsh, kernel etc
Note that when loading the PS3 Toolset you don't necessarily get the confirmation screen for the Flash 9 player plugin (I will use the acronym "FP" to refer to it in the rest of the post), it depends on previous user actions taken with that screen, the FP might already be enabled or disabled permanently if at some point in the past, while using the current user profile, you checked the "Don't show again" checkbox of the FP confirmation screen.
When the FP is permanently disabled OR when you don't accept to load the FP in the confirmation screen, the swf movies cannot be loaded & the Toolset automatically warns the user with a dialog box inviting to retry loading (refresh the web page in the browser).
If you get that Toolset warning about the FP without ever getting the FP confirmation screen, the Flash player is permanently disabled, you must try the workaround like Aldo explained ie use a new user profile.
When loading the PS3 Toolset, if you don't get any dialog box, warning you about the FP being unavailable & asking you to refresh the Web page, AND the Flash Memory Manager tab & the Userland memory editor tab get enabled after page initialization, the PS3 Toolset loaded successfully, you can safely proceed with your endeavours without having to worry about the Flash 9 player status.
i've been told that if i don't enable flash then it can result in a brick
You cannot brick because the Flash player is enabled/disabled, that's a myth, someone totally misunderstood the situation. Without the Flash player enabled, you cannot use the PS3 Toolset at all, never mind brick the console with it.
If you use the Flash Memory Manager (nothing to do with the Flash player, the Flash Memory refers to the contents of the console internal NOR/NAND chip) to jailbreak your console with Strict Mode on, the brick risk factor is 0 on the PS3 Toolset side.
Moreover, to guarantee that the jailbreak operations went smoothly, the Flash Memory Manager always double checks the integrity of the data it writes after writing it, if ever the checksums don't match the checksum of the patch data, the user is warned not to reboot & solve the issue ASAP. To my knowledge, nobody has ever reported seeing that warning yet, proof that the process is totally safe.
In theory, the only thing that could potentially brick your console would be a power cut occurring exactly within that very brief window of time where the NOR/NAND chip(s) get(s) written to. The resulting brick would be partial though & the system recoverable with a hardware flasher.
