A newly leaked Samsung Galaxy Tab firmware show that the Galaxy Tab have been shown to contain protected bootloaders that 'disables custom ROM flashing abilities'. Flashing to the leak has resulted in various reported unrecoverable bricks if Odin is used improperly to attempt to revert to a previous unprotected bootloader. If you want to maintain custom firmware flashing functionality, do not the JM6/A/C/D ROMs! This may indicate that Samsung is leaning towards limit custom firmware development by locking down the device. Sources Xda Thread: (WARNING! Do not flash jm6/A/C/D/E... Before reading this ! - xda-developers) XDA News: Warning: Leaked Galaxy Tab Firmware comes with Protected Bootloader | xda-developers
These ROM's the original post was referring to are ROM's developed for the TAB not the stock ROM's. If you read the posting about these ROM's you'll see they are custom ROM's. The Boot loaders are included in the custom ROM's and are not in the "normal" ROM. Original thread: [KERNEL][BETA][24.12.2010][CF-Root v1.4] JM6/A/C/D - su+busybox+CWM3/RFS - xda-developers
They have been working on a fix for the people that had installed the listed custom ROM's and I think Rotohammer has found a fix but I'd check on XDA to get the full scoop...
Honestly, I hate to say this, but this would not be a surprise long term. This is similar to the model Archos has always pursued and Apple has done with their builds. The ability to lock and control the ROMs is a major limitation for Androids to get products like NetFlix or buyin such as Military/Govt contracts. The DRM issue of Netflix is a real pain, but it makes ROMS like Archos or potentially Samsung a reality. The flipside of the consumer is impacted in loss of control. But it makes it a "stronger" product for security controls and inability for modding and placing a spyware rootkit.