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annotate compal-flash-boot-for-fc/README @ 992:a7b0b426f9ca

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target-utils: boot ROM UART autodetection revamped The new implementation should work with both the familiar Calypso C035 boot ROM version found in our regular targets as well as the older Calypso F741979B version found on the vintage D-Sample board.
author Mychaela Falconia <falcon@ivan.Harhan.ORG>
date Wed, 30 Dec 2015 21:28:41 +0000
parents 8eb7cb176a70
children
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8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
1 Compal phones have malicious wiring in their PCBs to disable Calypso's internal
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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2 boot ROM (nIBOOT input tied high instead of low). Therefore, flash sector 0
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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3 must always contain working boot code that allows the possibility of new code
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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4 download over the headset jack UART, and jumps to the main firmware in the rest
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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5 of the flash if no such download is taking place. In the absence of such good
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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6 boot code in flash sector 0 the phone is bricked.
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
7
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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8 Compal's own firmwares for these phones do feature a bootloader just as
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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9 described, but it has one defect: they put the boundary between the boot code
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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10 and the main firmware at address 0x2000, but the flash erase unit boundary
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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11 does not come until 0x10000. Therefore, every time the main fw needs to be
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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12 reflashed, flash sector 0 has to be erased and reprogrammed, creating a
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
13 bricking vulnerability.
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
14
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
15 Because Compal's original flash layout does not allow us to reuse their
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
16 bootloader totally untouched while replacing the main fw, and we'll have to
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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17 reflash our own version of the boot code at least the first time we reflash a
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
18 given phone from its official fw to FreeCalypso, we can take the liberty of
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
19 using a slightly patched version of Compal's boot code - with Compal's official
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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20 firmwares the bootloader part differs slightly from one fw version to the next
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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21 anyway.
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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22
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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23 The version of Compal's flash boot code built in this directory is intended to
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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24 be used with FreeCalypso firmwares. It is based on one of Compal's versions
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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25 that has no malicious features (no check of flash word 0x2060 and no requirement
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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26 of "1003" signature in the serially downloaded images at the most inconvenient
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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27 location), and it has been patched to transfer control to the main fw at 0x10058
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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28 instead of 0x20F8, i.e., main fw images are to be flashed at 0x10000 without
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
diff changeset
29 touching flash sector 0. Interrupt and exception version redirections have also
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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30 been patched accordingly; the specific interface between the boot code and the
8eb7cb176a70 compal-flash-boot-for-fc/README added
Mychaela Falconia <falcon@ivan.Harhan.ORG>
parents:
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31 main fw now mimics that of TI's TCS211 reference fw.