US5778070A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for protecting flash memory
Assignee: Intel Corp
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Filing: 1996-06-28
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Granted: 1998-07-07
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Expires: 2016-06-28
Abstract
Abstract In a computer system having a processor, a system memory, a flash memory, and a memory controller, a method comprising the steps of loading a flash memory upgrade program containing a new flash memory image and a digital signature into a portion of the system memory; configuring the memory controller to limit the processor to accessing only the flash memory and the portion of the system memory; verifying the flash memory update program using the digital signature; and, updating the flash memory only if the flash memory upgrade program is authentic.
Inventors
- 👤 Phillip E. Mattison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:29
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/56; G11C16/00; G11C16/02; G11C16/06; G11C16/22; G06; G06F; G06F12/00; G06F12/14; G06F12/1408; G06F12/1416; G06F12/1425; G06F12/1433; G06F21/00; G06F21/50; G06F21/57; G06F21/572; G11C16/10; G11C16/102; G11C16/105
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
91 words
In a computer system having a processor, a system memory, a flash memory, and a memory controller, a method comprising the steps of: loading a flash memory upgrade program containing a new flash memory image and a digital signature into a portion of said system memory; configuring said memory controller to limit said processor to accessing only said flash memory and said portion of said system memory; verifying said flash memory update program using said digital signature; and, updating said flash memory only if said flash memory upgrade program is authentic.
Claim 2
Dependent Claim
91 words
In a computer system having a processor, a system memory, a flash memory, and a memory controller, a method comprising the steps of: loading a flash memory upgrade program containing a new flash memory image and a digital signature into a portion of said system memory; configuring said memory controller to limit said processor to accessing only said flash memory and said portion of said system memory; verifying said flash memory update program using said digital signature; and, updating said flash memory only if said flash memory upgrade program is authentic.
Claim 3
Dependent Claim
53 words
The method of claim 1, wherein said loading step comprises: loading said flash memory update program into a set of addresses contained in said system memory, said set of addresses having a starting address and a length; loading a base register with said starting address; and, loading a limit register with said length.
Claim 4
Dependent Claim
38 words
The method of claim 2, wherein said configuring step comprises: providing a memory access disable signal to said memory controller; and, setting a memory address window detector to generate a memory access enable signal to said memory controller.
Claim 5
Dependent Claim
24 words
The method of claim 3, wherein said configuring step further comprises: providing a cache access disable signal to said memory controller and said processor.
Claim 6
Dependent Claim
49 words
The method of claim 1, wherein said verifying step comprises the steps of: decrypting said digital signature to obtain an original hash value; calculating an independent hash value for said flash memory update program; and comparing said original hash value and said independent hash value to determine a match.
Claim 7
Dependent Claim
31 words
The method of claim 1, wherein said updating step comprises: setting a flash memory programming enable register to enable programming of said flash memory; and executing said flash memory upgrade program.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-07-06 | 2002-01-05 | 2002-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-07-06 | 2006-01-05 | 2006-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-07-06 | 2010-01-05 | 2010-07-07 | $7700.00 | Window Closed / Lapsed |