Rhombus developed the SCE-51. A powerful small 8051 micro processor board with on board RAM and FLASHROM and bootloader.
In addition the board serves as an in circuit emulator.
Transferring your program to RAM goes very fast. Faster than loading it into the traditional FLASHROM. So during debugging it is well suited for debugging large applications.
There are many possibilities with this board and you have to look at www.rhombusinc.com for all the details.
A picture of the board is included here:
Since the help file must be kept small, the quality of the picture is poor.
A bootloader is integrated into BASCOM. Select the Rhombus SCE-51 programmer to enable it.