A: No. 4.90 is newer (April 2021) while 4.89 is from 2020. You must update to 4.90 to go online.
If your PS3 is connected to the internet, you can update directly without a USB drive: System Update Update via Internet
: Updates often address security vulnerabilities and combat system exploits or "jailbreaking".
Insert the USB drive into the rightmost USB port of your PS3 console. Go to the PS3 Home Menu and navigate to System Update Update via Storage Media
A USB flash drive formatted as FAT32 , and a computer.
: Official Sony patch notes state it "improves system performance".
: Sony’s official description was the classic, "This system software update improves system performance". The Real Purpose