Default bootloader

38 FB A5 00 EF 00 C2 30 A9 00 03 EF 01 EF 02 64
02 A9 00 05 85 04 A5 02 8D 80 03 E2 20 A9 04 8D
82 03 CB CD 82 03 F0 FA AD 82 03 F0 09 EF 82 E2
30 18 FB 4C 00 05 C2 20 A2 00 03 5C A0 40 00 42
92 04 E6 04 E6 04 88 D0 F6 E6 02 4C 16 04

    SEC
    XCE     ; Set emulation flag

    LDA 0
    MMU #0      ; Map disk drive

    REP #$30
    !al     ; 16-bit mode

    LDA #$300
    MMU #1      ; Set redbus window to $300
    MMU #2      ; Enable redbus

    STZ 2       ; Set 2 to zero

    LDA #$500
    STA 4       ; Put $500 in 4

    LDA 2
    STA $380    ; Set sector number to (2)

    SEP #$20
    !as     ; 8-bit mode for acc

    LDA #4
    STA $382    ; Read disk sector

-   WAI     ; Wait a tick

    CMP $382    ;                   Why compare it to A instead of #0?
    BEQ -       ; not ready yet, jump back

    LDA $382
    BEQ +       ;                   This makes absolutely no sense

    MMU $82     ; Disable Redbus

    SEP #$30
    !al     ; 8-bit for all

    CLC
    XCE     ; Clear emulation flag

    JMP $500    ; Execute loaded code

+   REP #$20
    !al

    LDX #$300
    TXI     ; WTF?

    LDY #$40
    NXA

    STA (4)
    INC 4
-   INC 4

    DEY

    BNE -

    INC 2

    JMP $416