Sorry Marcin, but don't have any good news. You have to call customer support, then can generate a temporary BootRrom password for you.
In order to recover (reset) the SW4500 BootRom password the following actions are required:
1. The SW4500 Serial Number and MAC Address need to be obtained (located on a label on the rear of the switch)
2. The customer needs to indentify 3Com that they are the legal owners of the SW4500 and this corresponds to the register in the 3Com Warranty Registration system
3 The customer needs to contact 3Com Product Support with (1) and (2)
Best of luck,
RK